Crop Profile for Apples in Virginia

Biological Control: Natural predators of GA (AA and SA) are similar to those discussed for RAA. Control is likely to occur if greater than 20% of the aphid colonies have predators.

Cultural Control: Removal of watersprouts in the center of trees may reduce GA population levels.

Spotted Tentiform Leafminer, Phyllonorycter blancardella (Fabricius)--4

Three generations of the spotted tentiform leafminer (STLM) occur throughout commercial fruit producing areas in Virginia. STLMs cause damage by mining within the leaf tissue resulting in premature fruit drop and also reduced quality and quantity of the apples remaining on the tree. Fruit set for the following year may be affected as a result of the decreased ability of leaves to properly photosynthesize adequate amounts of photosynthate. STLM resistance to organophosphate insecticides has developed in some orchards within the state.

Monitoring: Pheromone traps are available for STLMs. They are placed in the orchard during the silver tip stage at about chest height. At present, there is no correlation between the number of leafminers caught and the economic damage. However, examinations of fruit cluster leaves for the presence of mines may begin at petal fall in order to determine the necessity of treatment.

• abamectin (Agri-mek)-PHI-28 days. Formulated as an emulsifiable concentrate for STLM control at petal fall. Efficacy is increased when applied in combination with spray oil at the recommended rate of 0.01-0.02 lb. a.i./acre. Should not be applied more than twice per season. REI-12 hours.
• esfenvalerate (Asana XL)-PHI-7 days. Pyrethroid insecticide formulated as an emulsifiable concentrate, providing broadspectrum insect control at comparatively low application rates (0.25-0.75 lb. a.i./acre). Suggested for use during the prebloom period given high toxicity to mite and other beneficial predator populations. Do not exceed 0.525 lb. a.i./acre/season. REI-12 hours.
• imidacloprid (Provado 1.6F)-PHI-7 days. Formulated as a flowable and applied at a rate of 0.05-0.1 lb. a.i./acre for first generation control at petal fall and then additional control beginning with the second cover spray and continuing throughout the growing season. Toxic to bees and aquatic organisms. REI-12 hours.
• methomyl (Lannate 90SP)-PHI-14 days. Limited systemic carbamate insecticide used to provide STLM control when applied at a rate of 0.70 lb. a.i./acre. If used alone, does not provide control beyond 3-4 days. Do not apply more than 5 applications per crop. REI-(72-96) hours.
• oxamyl (Vydate)-PHI-14 days. Multipurpose carbamate-class chemical used for insect, mite, and nematode control and also as a plant growth regulator. Applied to foliage at a rate of 0.75 lb. a.i./acre to control STLMs during the late bloom period. Do not exceed four treatments per growing season. REI-48 hours.
• permethrin (Ambush) (Pounce)-PHI-7 days. Nonsystemic pyrethroid insecticide, which provides excellent control of many organophosphate-resistant insects. Ambush 2EC can be applied at a rate of 0.125-0.1875 lb. a.i./acre and Pounce 3.2EC at a rate of 0.1875 lb. a.i./acre for STLM control. Not recommended for use after bloom to prevent outbreaks of harmful mites. REI-24 hours.

Biological Control: A complex of predators and parasitoids exert control on STLM in most commercial orchards. Two of the most common parasites are Sympiesis marylandensis Girault and Pholetesor ornigis (Weed). Earthworms may also destroy leafminer overwintering habitats by eliminating leaves found on the ground beneath the apple tree.

Cultural Control: None that are commercially effective.

San Jose Scale, Quadraspidiotus perniciosus (Comstock)--5

San Jose Scale (SJS) was introduced into the United States in 1870 and has been responsible for the death of thousands of acres of fruit trees. Part of the difficulty in managing SJS has resulted from the fact that it spends most of its life cycle under a secreted waxy covering. First generation crawlers (mobile stage) emerge from this covering 4-6 weeks after bloom to feed on tree sap. The crawler stage can be dispersed either by birds, humans or machinery to new locations on the trunks and branches of hosts. As feeding progresses, the crawler becomes attached to the tree and begins to develop the protective covering characteristic of this pest. The scale insects are also capable of feeding on leaves and fruit, with large populations resulting in drastic reductions in tree productivity. At present, control of SJS is achieved through the use of currently available chemicals; except in cases where sprays are unable to penetrate the tree canopy. Typically this occurs in orchard blocks containing older, standard sized or poorly pruned trees. Usually 2-3 generations of SJS affect apples produced in Virginia.

Monitoring: Pheromone traps may be used to monitor the flight of adult males. In an ideal situation, these traps are placed in previously infested blocks to aid capture. Traps should be checked daily until the first male is caught. Crawler emergence typically occurs 300-350 degree days after the initial trap catch for all generations. Double-sided sticky tape placed around the limbs can also be used to evaluate crawler emergence. The latter method is usually the most reliable technique for monitoring crawlers and hence timing of chemical control applications.

Chemical Control: Insecticide applications are recommended if 1% of the fruit from the previous season showed SJS damage.

• azinphos-methyl (Guthion)-PHI-7 days. Broadspectrum organophosphate insecticide formulated both as a wettable powder and also as an emulsifiable concentrate. Applied separately at a rate of 0.75 lb. a.i./acre or in combination with methomyl at a rate of 0.5 lb. a.i./acre. Low rate of predator toxicity. Use should be monitored to avoid insect resistance. REI-48 hours.
• chlorpyrifos (Lorsban 4E)-PHI-28 days. Organophosphate insecticide formulated as an emulsifiable concentrate for early season control of SJS. Applied at a rate of 1.0 lb. a.i./acre either separately or in combination with oil (see rate below). Should not be used more than 8 times per season (21 days between last two applications). REI-24 hours.
• imidacloprid (Provado 1.6F)-PHI-7 days. Formulated as a flowable and applied at a rate of 0.05-0.1 lb. a.i./acre for control of SJS at petal fall. Toxic to honey bees and aquatic invertebrates. REI-12 hours.
• methidathion (Supracide) - Nonsystemic organophosphate insecticide available as both a wettable powder and an emulsifiable concentrate. Very effective against SJS when applied as dormant or delayed dormant sprays. Should not be applied after blossoms open. Combination with alkaline solutions will reduce its residual toxicity. REI-48 hours.
• methomyl (Lannate 90SP)-PHI-14 days. Limited systemic carbamate insecticide used to control SJS when applied in combination with azinphos-methyl, phosmet or oil at a rate of 0.35 lb. a.i./acre. Do not apply more than 5 applications per crop. REI-(72-96) hours.
• methyl parathion (Penncap-M)-PHI-14 (21 if over 4.0 pt./acre). Organophosphate insecticide available in a microencapsulated formulation to improve applicator safety. Applied at a rate of 0.75 lb. a.i./acre to control SJS. Fits well into IPM programs given its low rate of beneficial predator toxicity. Sprays made during crop or groundcover bloom may affect honey bees. No more than 5 applications are permitted from petal fall to harvest. REI-48 hours.
• phosmet (Imidan 70W)-PHI-7 days. Broadspectrum organophosphate formulated as a wettable powder and applied at a rate of 1.5 lb. a.i./acre to control SJS. Low rate of beneficial predator toxicity. REI-24 hours.

• Superior Oil-applied separately or in combination with Lorsban 4E at a rate of 2 gal./100 gal. of water to control overwintering stages of SJS.

Biological Control: Female scales may be parasitized by the wasp, Prospaltella pernicius.

Cultural Control: Annual dormant pruning, especially of large, standard-type trees, improves spray coverage and reduces the severity of this pest.

Potato Leafhopper, Empoasca fabae Harris--6

The potato leafhopper (PLH) affects young apple trees within Virginia by causing what is referred to as "hopperburn". Hopperburn results from the injection of toxic saliva that reduces the availability of water and nutrients to young leaves by collapsing the xylem and phloem tubes. This, in turn, causes the edges of infested leaves to curl downward; first turning lighter green, then yellow, and finally brown and necrotic. The PLH overwinters in the Gulf Coast states, reentering the Mid-Atlantic region each spring to complete several (usually 2-4) overlapping generations. PLHs affect a number of other hosts in addition to apple, including alfalfa, potato and grape.

Monitoring: Young blocks of trees should be frequently inspected for the presence of PLH beginning in mid-May. Although no thresholds are currently available, treatment should be applied following appearance of the first adults.

Chemical Control: Broadspectrum organophosphates work moderately well to control this insect given that resistance has not yet been developed by the PLH to this type of chemistry. However, imidacloprid provides the most effective chemical control.

• azinphos-methyl (Guthion)-PHI-7 days. Nonsystemic organophosphate insecticide providing broadspectrum control of non-resistant insects. Formulated both as a wettable powder and also as an emulsifiable concentrate. Applied at a rate of 0.75 lb. a.i./acre for the moderate control of PLH; allow 7 days between sprays. Fits well into IPM programs given its low rate of predator toxicity, however use should be monitored to avoid insect resistance. REI-48 hours.
• imidacloprid (Provado 1.6F)-PHI-7 days. Formulated as a flowable and applied at a rate of 0.05-0.075 lb. a.i./acre for excellent control of PLH at petal fall. Toxic to honey bees and aquatic invertebrates. REI-12 hours.
• methyl parathion (Penncap-M)-PHI-14 (21 if over 4.0 pt./acre). Organophosphate insecticide available in an encapsulated formulation to improve applicator safety. Applied at a rate of 0.75 lb. a.i./acre to control PLH. Fits well into IPM programs given its low rate of beneficial predator toxicity. Honey bees may be seriously affected by applications made during crop or groundcover bloom. Should not exceed 5 applications from petal fall to harvest. REI-48 hours.

Biological Control: Natural enemies of PLH are present within Virginia orchards, however, they do not generally react fast enough to prevent hopperburn.

Cultural Control: Growers may decrease the likelihood of PLH damage by avoiding planting alfalfa in close proximity to orchard blocks.

TwoSpotted Spider Mite, Tetranychus urticae Koch--7

The twospotted spider mite (TSM) is usually of secondary importance to the ERM within orchards in Virginia, although it is of primary importance in other areas of the world. The twospotted spider mite has an extremely broad host range encompassing upwards of 150 economically important species. Adult female TSMs overwinter in the orchard ground cover, feeding on various weed species. During the spring and early summer, TSMs move from the ground cover into the tree canopy. Feeding results in injury similar to that caused by ERM, however TSM usually cause greater damage to host leaf function in a shorter amount of time.

Monitoring: May be carried out in conjunction with ERM sampling. Under most situations, TSM may be added in with the ERM populations. In the event that TSMs are the predominant species, an action threshold of half the recommended value for ERM should be used.

Chemical Control: Treatments to control TSMs as with ERMs are typically targeted at the overwintering eggs during the prebloom period and at the motile stages during the post-bloom period. Monitoring of motile stages will help to determine the number of post-bloom applications needed. See the ERM description for specific chemical information.

Alternate Control: Similar to that described under the ERM section.

Biological Control: Natural predators of the TSM are identical to those attacking the ERM. Control will occur if the number of S. punctum larva and adults is at least 2.5 times as abundant as the number of twospotted spider mites per leaf during a 3 minute scouting period.

Cultural Control: Elimination of groundcover that fosters the TSM during the winter, may reduce population size for the following spring.

Lyonetia leafminer, Lyonetia speculella Clemens--8

The lyonetia leafminer (LL) was first discovered within commercial apple orchards in Virginia in the early 1980’s. Typically the LL attacks young, non-bearing trees, given the large potential leaf area. Mining injury is similar to that described for the STLM, with increased severity on new succulent leaves. Research is presently being conducted to determine the life cycle of this organism, however, apple and other fruit trees do appear to serve as primary hosts.

Monitoring: Young and non-bearing trees should be examined for the presence of mines. However, no thresholds are currently available to aid in the necessity of treatment.

Chemical Control: Control of the LL is identical to that recommended for STLMs.

Burr Knot Borers--9
Dogwood Borer, Synanthedon scitula (Harris)
Apple Bark Borer, Synanthedon pyri (Harris)

Dogwood borers (DB) and apple bark borers (ABB) infest the above ground adventitious root primordia or "burr knot" portion of clonal rootstocks. Both are classified as clearwing moths (sesiids), the larva of which bore into host wounds causing reduced plant vigor and yield and possibly death. The DB has a broad host range and is the main species causing damage. Two generations of DB are noted within Virginia, with peak activity of the first generation occurring between late July into early August. An additional later peak has been noted in August, usually resulting in the greatest injury to apple trees. The ABB has a more specific host range and is less likely than the DB to attack healthy trees.

Monitoring: Pheromone traps are used to monitor borer populations and also to aid in the timing of insecticide applications. Placement of traps is critical to ensure correct data--4 feet from the ground for DB. In Virginia, lilac borer traps have been found to be more effective for capturing DB than the DB traps. Burr-knots may also be examined for the presence of protruding pupal skins.

Chemical Control: Insecticide applications should be directed at the lower trunk region of trees to prevent larval infestation of burr knots.

• chlorpyrifos (Lorsban 4E)-PHI-28 days. Organophosphate insecticide formulated as an emulsifiable concentrate for mid-season borer control. Applied at a rate of 1.0 lb. a.i./acre. Typically provides better control than endosulfan. Should not be used more than 8 times per season (21 days between last two applications). REI-24 hours.
• endosulfan (Thiodan 50W)-PHI-21 days. Nonsystemic organochlorine insecticide used to control borers when applied as a foliar spray at a rate of 1.5 lb. a.i./acre concentrate. Should not be applied more than three times to apples during the fruiting period. Endosulfan is highly poisonous and should be used with caution. REI-24 hours.

Biological Control: None that are commercially effective.

Cultural Control: Incidence of burr knot borers can be reduced by the removal of spiral-wrap and other types of tree trunk guards that promote burr knot formation and prevent spray coverage. Maintenance of healthy trees and also coverage of burr knots with soil will prevent infestation.

White Apple Leafhopper, Typhlocyba pomaria McAtee--10

The white apple leafhopper (WALH) is a foliage-feeding insect native to the eastern U.S. As its name suggests, the primary host is apple. Low populations of the leafhopper can be tolerated within commercial orchards, but moderate to high populations may lead to indirect fruit damage in the form of sooty molds. Damage from nymphal feeding on the underside of leaves results from the insertion of their stylet through the first or second layer of pallisade cells. Heavy injury, especially under high crop loads, may result in downsizing of fruit due to the decreased photosynthetic ability of the leaves. Feeding is readily evidenced by the stippling pattern visible on injured leaves, which may cause the severity of WALH damage to be overestimated. Stippling is not only a result of cell destruction, but also of the reflection of light by air, which has filled the damaged areas. Adult WALH are not considered to be as damaging as nymphs given their shorter feeding pattern and smaller stylet. However, adults may be a nuisance to pickers at harvest. Although current spray programs maintain WALH populations at a minimum, there is recent evidence of WALH resistance to organophosphates.

Monitoring: Randomly selected leaves should be examined for nymphs from the period of petal fall to the first cover spray, to determine the necessity of chemical application. If counts reveal an average of 3 nymphs/leaf over 10 leaves, treatment should occur regardless of crop load. Second generation thresholds are the same as the first except that large crop load is a factor.

Chemical Control: Insecticide applications to control WALH can begin as early as petal fall depending on the first generation pest pressure and may need to be reapplied during the 5^th cover spray for second generation leafhoppers. It should also be noted that the second generation is present over a more protracted period than the first.

• formentanate hydrochloride (Carzol 92SP)-PHI-7 days. Nonsystemic carbamate miticide/insecticide recommended for use at a rate of 0.70 lb. a.i./acre for controlling WALH. This product is highly toxic to predatory mites, therefore, care should be taken to time applications properly. Effective against most organophosphate-resistant insects. REI-48 hours.
• azinphos-methyl (Guthion)-PHI-7 days. Nonsystemic organophosphate insecticide providing broadspectrum control of non-resistant insects. Formulated both as a wettable powder and also as an emulsifiable concentrate. Applied at a rate of 0.75 lb. a.i./acre for the control of WALH; allow 7 days between sprays. Fits well into IPM programs given its low rate of predator toxicity, however use should be monitored to avoid insect resistance. REI-48 hours.
• imidacloprid (Provado 1.6F)-PHI-7 days. Formulated as a flowable and applied at a rate of 0.05-0.1 lb. a.i./acre for control of WALH at petal fall. Toxic to honey bees and aquatic invertebrates. REI-12 hours.
• methomyl (Lannate 90SP)-PHI-14 days. Limited systemic carbamate insecticide used to provide WALH control when applied at a rate of 0.70 lb. a.i./acre. However, if used alone, does not provide control beyond 3-4 days. Do not apply more than 5 applications per crop. REI-(72-96) hours.

Biological Control: An egg parasite, Anagrus epos Girault, overwinters inside the eggs of WLH and also attacks eggs during the summer. Predatory mirids and spiders may attack nymphs, especially in the second generation.

Cultural Control: None that are commercially effective.

Prionus Borors--11
Prionus Borer, Prionus imbricornis (Linnaeus)
Broadnecked Root Borer, Prionus laticollis (Drury)

A complex of the two prionus borers, P. imbricornis and P. laticollis are common in the mountainous regions of Virginia. This complex has a wide host range, with damage resulting from larval boring in the root area of a given tree. Young larvae first feed on the root surface in the spring, but as they grow they begin to enter the roots, hollowing or girdling them during the winter months. Pupation takes place the following spring; the pupal stage lasts about 3 months.

Monitoring: Declining trees may be examined for the presence of large larvae or for distinctive tunneling either through the use of hand trowels around the crown area or by the uprooting of trees in severe cases.

Chemical Control: More data will be needed to determine the exact chemical control method for this pest.

Biological Control: None that are commercially effective.

Cultural Control: None that are commercially effective.

Climbing Cutworms--12

The group of cutworms known as the climbing cutworms tends to climb fruit and ornamental trees in the spring and feed on the foliage at night. The dingy cutworm, Feltia faculifera (Guenée), spotted cutworm, Xestia c-nigrum (Linnaeus), darksided cutworm, Euxoa messoria (Harris), variegated cutworm, Peridroma saucia (Hübner), mottled cutworm, Abagrotis alternata (Grote), and w-marked cutworm, Spaelotis clandestina (Harris) are the most common and widely distributed of the climbing cutworms found in Virginia. Generally, cutworm damage is sporadic, however, young trees, especially those planted in sandy soils may be prone to severe damage. Damage results from defoliation of buds, blossoms and leaves, primarily at the tops of trees and ends of limbs.

Monitoring: Cutworms can be detected either as they overwinter in the leaf litter at the base of the tree or as they begin feeding in the spring. Buds in the lower center of the tree should be checked first for evidence of feeding. Cutworm presence may not be detected given their tendency to feed at night.

Chemical Control: Chemical treatments can be applied once cutworm presence has been detected. Given the sporadic nature of this pest, no thresholds have been established. In addition to those chemicals listed below broadspectrum organophosphate insecticides may also be used to control climbing cutworms.

• Bacillus thuringiensis or Bt (various trade names)-PHI-0 days. Exotoxins produced by the bacterium, Bacillus thuringiensis, have been formulated for the control of insect pests attacking tree fruit crops. Insect pests must ingest the toxins therefore, Bts are only effective against larvae, not eggs. When compared with conventional spray schemes containing organophosphates, more Bt applications will be necessary to maintain a similar level of control. Bts are generally safe for applicators and most nontarget species, however, certain formulations may be toxic to honey bees and other natural enemies exposed to direct spray. REI-12 hours.
• esfenvalerate (Asana XL)-PHI-7 days. Pyrethroid insecticide formulated as an emulsifiable concentrate, which provides broadspectrum insect control at comparatively low application rates (0.25-0.75 lb. a.i./acre). Suggested for use during the prebloom period given high toxicity to mite and other beneficial predator populations. Do not exceed 0.525 lb. a.i./acre/season. REI-12 hours.
• permethrin (Ambush) (Pounce)-PHI-7 days. Nonsystemic pyrethroid insecticide, which provides excellent control of many organophosphate-resistant insects. Ambush 2EC can be applied at a rate of 0.125-0.1875 lb. a.i./acre and Pounce 3.2EC at a rate of 0.1875 lb. a.i./acre for STLM control. Not recommended for use after bloom to prevent outbreaks of harmful mites. REI-24 hours.

Biological Control: None that are commercially effective.

Cultural Control: None that are commercially effective.

Periodical Cicada, Magicada spp.--13

The periodical cicada has a broad host range within which apple is included. Damage results primarily from branch wounding due to oviposition, which also causes death in the region distal to the wound. Feeding by nymphs among the roots may also lead to damage, but usually to a much lesser degree. Injury due to the cicada does not occur every year, however, it may be extremely severe in instances where periodical emergence is scheduled to occur. This may be every seventeen or thirteen years, although overlapping broods could increase occurrence.

Monitoring: Evidence of the cicada or cicada presence should be monitored during years when adult emergence is expected. Maps are available which predict current outbreaks based on previous emergence data.

Chemical Control: Treatment should begin when aggregations of cicada are found within the orchard.

• methomyl (Lannate 90SP)-PHI-14 days. Limited systemic carbamate insecticide formulated as a soluble powder. Only form of chemical treatment (0.70 lb. a.i./acre), which offers excellent control against the cicada. Do not apply more than 5 applications per crop. REI-(72-96) hours.

Biological Control: Parasitic wasps and flies and predatory mites are the most significant natural enemies of periodical cicada eggs. Adults may be attacked by birds or killer wasps, however, the wasps are usually timed for later emerging annual cicadas. Massospora cicadina, a fungal pathogen also infects the adults. Naturally occurring enemies provide insufficient commercial control of the periodical cicada during years of severe outbreak.

Cultural Control: Delaying planting within the year of, or the year prior to expected emergence may prove beneficial, especially since periodical cicada damage is most detrimental among young trees.

Woolly Apple Aphid, Eriosoma lanigerum (Hausmann)--14

The woolly apply aphid is a gall-forming pest that can establish colonies either aerially or on roots. In Virginia, injuries to the roots are the more common than aerial damage. Generally, most mature trees have some degree of root infestation, however, WAA are usually damaging only to young trees (stunted growth). Although the life history of the WAA is not yet well understood, it has been noted that high soil temperatures, weed cover, and distant spacing of trees inhibit the spread of the crawler (mobile) stage between trees.

Monitoring: Healed wounds or pruning cuts may be monitored in mid- to late summer for the excessive presence of branch colonies.

• endosulfan (Thiodan 50W)-PHI-21 days. Nonsystemic organochlorine insecticide used to control WAA when applied as a foliar spray at a rate of 1.5 lb. a.i./acre concentrate. Should not be applied more than three times to apples during the fruiting period. Endosulfan is highly poisonous and should be used with caution. REI-24 hours.

Biological Control: Woolly apple aphid populations can be adversely affected by the presence of natural aphid predators, with Aphelinus mali (Haldemann) producing the greatest control. A. mali, however, is very sensitive to post-bloom applications of carbamate and pyrethroid insecticides.

Cultural Control: Root infestations are lower on the Malling Merton (MM) series of rootstocks due to resistance breeding.

Apple Rust Mite, Aculus schlechtendali (Nalepa)--15

Apple rust mites (ARM) are commonly found within managed orchard blocks in Virginia, however damage will result only if population levels are high. Large ARM populations cause leaves to curl lengthwise and turn brown and/or young fruit to be russetted. Low numbers of ARM may actually benefit IPM programs by serving as additional food sources for beneficial mite predators. ARM can condition foliage so that it is less suitable for the ERM (more damaging) development.

Monitoring: Leaf examinations using a hand lens will aid in the identification of potentially damaging numbers of ARM. In situations where russetting is of concern, the interiors of bud scales may also need to be examined to determine the amount of overwintering eggs.

• endosulfan (Thiodan 50W)-PHI-21 days. Nonsystemic organochlorine insecticide used to provide effective control of ARM when applied as a foliar spray at a rate of 1.5 lb. a.i./acre concentrate. Highly poisonous--should be used with caution. REI-24 hours.

Biological Control: Natural mite predators may use ARM as alternative food sources to ERM.

Cultural Control: None that are commercially effective.

Gypsy Moth, Lymantria dispar (Linnaeus)--16

All instars of gypsy moth caterpillars will attack apple trees causing defoliation that could be especially damaging to young trees. After emergence, female moths deposit egg masses on or around the trees for hatch the following year (1). Orchards may also be infested by "ballooning larvae which travel long distances on silk threads.

Monitoring: Trees should be inspected around petal fall for the presence of gypsy moth larvae. If found, larvae specific control methods should be undertaken.

Chemical Control:

• azinphos-methyl (Guthion)-PHI-7 days. Nonsystemic organophosphate insecticide providing broadspectrum control when applied at a rate of 0.75 lb. a.i./acre; allow 7 days between applications. Formulated both as a wettable powder and also as an emulsifiable concentrate. Low rates of natural predator toxicity. Monitor use to avoid insect resistance. REI-48 hours.
• Bacillus thuringiensis (Dipel) (Thuricide)-Naturally occurring microorganism formulated for the control of certain insects. Timing of application is crucial. Applied either when eggs have hatched and leaves are expanding or when young caterpillars are present. Generally not as effective as organophosphate treatments and must be applied more often.
• carbaryl (Carbaryl) (Sevin)-PHI-1 day. Carbaryl is a carbamate insecticide available in two formulations, (Sevin) and/or (Sevin XLR Plus).. Application rates are as follows, 3.0 lb. a.i./acre of Sevin and 0.75-1.0 lb. a.i./acre of Sevin XLR Plus for control of gypsy moth. Sevin is highly toxic to honey bees and mite predators and should not be used near bloom or in long-season control programs. Sevin XLR Plus is less hazardous to bees and other beneficial insects and also provides a longer period of residual activity. Should be applied when eggs are hatched and leaves are expanding or when young caterpillars are present. REI-12 hours.
• methomyl (Lannate 90SP)-PHI-14 days. Limited systemic carbamate insecticide applied at a rate of 0.70 lb. a.i./acre. Do not apply more than 5 applications per crop. REI-(72-96) hours.
• phosmet (Imidan 70W)-PHI-7 days. Broadspectrum organophosphate formulated as a wettable powder and applied at a rate of 1.5 lb. a.i./acre to control gypsy moth. Can be applied when caterpillars are present. REI-24 hours.

Biological Control: Gypsy moth may be attacked and killed by the fungus, Entomorphaga maimaiga. Research is pending as to the large scale feasibility of this method of control.

Cultural Control: Physical removal and subsequent destruction of egg masses will reduce gypsy moth damage. However, this technique is not usually cost-effective within commercial operations.

Flatheaded Apple Tree Borer, Chrysobothris femorata (Olivier)--17

Flatheaded apple tree borers (larval stage) colonize weakened or injured hardwoods, either by producing large deadened patches of bark via mines and tunnels or by girdling the tree and causing death. Typically these insects do not cause problems within thriving Virginia orchards given their tendency to attack only weak or damaged trees.

Monitoring: No monitoring techniques in use at present.

Chemical Control: Specific chemicals have not been needed to control this pest given the existing management practices within many commercial orchards, specifically those targeted for tree health. At present, there are no satisfactory chemicals available to control the flatheaded apple tree borer.

Biological Control: None that are commercially effective.

Cultural Control: Proper maintenance of trees to stimulate healthy growth and development will deter the flatheaded apple tree borer. Also, the use of mechanical barriers such as paper or burlap around the base of pruned or transplanted trees will prevent injury (8).

Apple Grain Aphid, Rhopalosiphum fitchii (Sanderson)--18

The apple grain aphid (AGA) usually causes little or no injury to apples produced commercially in Virginia. It does, however, initiate early concern as AGA nymphs are the first to appear on apple buds in the spring; approximately 7-10 days earlier than green or rosy apple aphids. Eggs of the AGA overwinter on apple, but third generation winged adults also utilize various grass species as secondary hosts during the late spring and summer. Additional generations are produced on the grasses before winged migrants return to apple and other primary tree fruit hosts for mating.

Monitoring: No monitoring techniques in use at present.

Chemical Control: Given that injury as a result of this pest is rare, no chemical control has been recommended at this time.

Biological Control: Aphid predators such as those discussed for the RAA would prey on this species, however the AGA has usually moved on to its secondary host by the time natural predators have emerged.

Cultural Control: None that are commercially effective.

Relative Effectiveness of Chemicals for Apple Insect Control:

While there has been a gradual decline in apple acreage over the past 25 years, total production has remained fairly constant because of increased efficiency. Improved production efficiency is related to improved production methods, retention of better sites, and higher density plantings. A continuing trend toward more trees per acre in Virginia orchards has resulted in more apple trees now planted on 18,278 acres than were planted on 41,023 acres in 1963 and more bearing trees than were planted on 55,853 acres in 1956. These are positive indicators of the health of the Virginia fruit industry, but some old disease problems continue to impact tree fruit production, and some potentially serious, new disease problems are anticipated for the rootstocks of the new high density plantings.

More than 15 diseases of economic importance affect apples in Virginia. Annual disease losses are greatly affected by weather conditions and may vary widely from orchard to orchard and from region to region within the state. Losses in both cases usually become more severe over a period of years that favor disease development. Several diseases such as scab and the rots can cause losses of more than 90% in poorly controlled disease situations. Monitoring of threatening diseases, improving cultural control practices, and timely application of fungicides have provided acceptable management programs for most of these diseases.

The development of resistance to dodine, the benzimidazole and to the sterol inhibiting fungicides by some fruit pathogens has reduced the effectiveness of these fungicides on some diseases in Virginia. Two new classes of fungicides are now coming available for commercial use, cyprodonil (Vangard), an anilinopyrimidine, and kresoxim-methyl (Sovran), a broad-spectrum strobilurin fungicide. However, both of these new fungicides are also at risk for development of resistance. As a result, management strategies to avoid such resistance will be important as these classes come into commercial usage.

Fireblight, a devastating bacterial disease, is increasingly becoming a higher management priority to growers throughout Virginia and the mid-Atlantic region. Factors related to the increased prominence of this disease include more plantings of highly susceptible scion/rootstock combinations, and the use of crabapple pollinizers within high-density orchards. Streptomycin resistance by the fireblight bacterium, Erwinia amylovora, has not yet been proven in the mid-Atlantic region. However, this concern, and the increasing planting of highly susceptible scions and rootstocks, heightens the need to avoid cultural practices that increase tree susceptibility. In addition to chemical control, a prudent program for the overall management of fireblight should also include proper tree nutrition, avoiding excessive fertility, and utilizing practices that promote early cessation of growth.

Because pressures to reduce pesticide use are likely to continue for the foreseeable future, apple cultivars with genetic resistance to diseases may become more important as the options for chemical control of apple pests become more limited. Cooperative breeding programs initiated 50 years ago to develop apple cultivars with resistance to scab, have provided certain combinations, which may be suitable for Virginia's prominent fruit processing industry. Although all of these cultivars would permit reduction in fungicide usage as far as scab management is concerned, further screening of these cultivars is desirable for susceptibility to powdery mildew, rusts, sooty blotch, flyspeck, Brooks spot, and rot diseases in the mid-Atlantic region.

Disease Pests

Disease descriptions and control recommendations found below were modified from information presented in the 1999 Spray Bulletin for Commercial Tree Fruit Growers (VA, WV and MD Cooperative Extension) (3) and in the WVU Index of Fruit Disease Photographs, Biology, Monitoring and Management Information (9).

Fungicides and Bactericides: A table of effectiveness of apple fungicides on diseases in Virginia has been included at the end of this section. Effectiveness ratings are based on research conducted at Blacksburg and Winchester, VA, and also on research from surrounding states. The results listed in this table may vary depending on weather conditions, how well the trees were sprayed the previous year, concentration of inoculum present, tree size and age, formulation of a given fungicide and how the fungicide was applied.

DISEASES--ATTACKING FRUIT AND FOLIAGE

Ranked in order of importance to the production of peaches in Virginia (1=most important)

Apple Scab, Venturia inaequalis (Cooke) G. Wint.--1

Apple scab is one of the most damaging diseases in Virginia orchards. The fungus, which produces this disease, Venturia inaequalis, directly attacks apple buds, leaves and fruit during the spring months, resulting in calling or downgrading of the fruit and reduction in bloom in severe cases. Losses are greatest when cool, humid conditions prevail resulting in the occurrence of "scab" lesions.

Monitoring: Monitoring is mainly a function of subsequent apple scab control. Orchards should be examined for evidence of infection and if discovered, these areas should be tagged and considered in early season treatment decisions for the following growing season. The length of required wetting periods for scab infection is well-known, therefore infection periods should be recorded for management purposes.

Chemical Control: The apple scab fungus overwinters in infected leaves that have fallen to the ground. As spring approaches, fruiting bodies on fallen leaves release spores to coinciding with the 1/4-1/2 inch green stage until 2-3 weeks after petal fall. Fungicide application is critical during this period. Usually, sterol-inhibiting fungicides (SIF) are applied from the 1/4-1/2 inch green stage through the last cover spray in combination with a protectant such as captan or an EBDC fungicide. The recommended SIFs include myclobutanil (Nova 40W), fenarimol (Rubigan 1E) and triflumizole (Procure 50WS) and are applied at fairly low rates depending on the formulation. EBDC fungicides (mancozeb, metiram and ziram) are applied at rates of 2.3, 2.4 and 4.9 lb. a.i./acre, respectively, while captan is applied at 3.0 lb. a.i./acre. The scab fungus has become resistant to the benzimidazole fungicides in many areas of Virginia.

Biological Control: None that are commercially effective.

Cultural Control: Sanitation practices (i.e. leaf pick-up, leaf shredding, urea applications) along with use of resistant cultivars provides variable control against apple scab. Earthworms help to reduce primary inoculum.

Powdery Mildew, Podosphaera leucotricha (Ell. & Ev.) E.S. Salmon--2

Powdery mildew primarily affects the leaves, however in severe cases net-like russetting occurs on the fruit and fruit yields are reduced. Cultivars vary widely in their sensitivity to powdery mildew. In the case of susceptible trees, a mildewcide should be applied in addition to the regular fungicide applications made throughout the growing season.

Monitoring: Trees should be monitored during the growing season to ascertain strengths and weaknesses in the current spray program. Foliar disease incidence greater than 20% indicates a potential reduction in yield.

Chemical Control: Fungicide applications should begin at tight cluster and continue until terminal growth has ceased in the summer. Sterol-inhibiting fungicides (SIF) are highly effective. The recommended SIFs include myclobutanil (Nova 40W), fenarimol (Rubigan 1E) and triadimefon (Bayleton 50DF) and are applied at fairly low rates depending on the formulation. Application intervals are usually 7 days during the early season and 12-14 days following bloom. Sulfur materials are also economically effective protectants against mildew if a 7-day interval is maintained, but can cause fruit russetting of some cultivars and should be avoided during extremely hot weather.

Biological Control: None that are commercially effective.

Cultural Control: Terminals, which appear white-silver colored, may be pruned out during the dormant stage to reduce the amount of inoculum present at the start of the next growing season.

Fire Blight, Erwinia amylovora (Burrill) Winslow et. al.--3

Fire blight is an extremely destructive bacterial disease, which does irreparable damage to apple trees throughout the Mid-Atlantic region. Fire blight occurs sporadically both within orchards and across years. Initial infection occurs in the early season during bloom periods with warm wet weather, then once established, spread is facilitated through insect feeding or other forms of injury that allow for bacterial entry. Late season infections may result if shoot growth continues past mid summer. This also increases the amount of overwintering inoculum.

Monitoring: Examination of orchard blocks with a history of fire blight is a critical step in controlling the spread of the disease. Another important aspect of control involves the monitoring of weather conditions that facilitate the build-up of inoculum in the orchard, the blossom infection process and the appearance of symptoms. A specific type of weather station is required for this task, however local extension agents will most likely provide this information. If fire blight is detected, blighted limbs or possibly whole trees may need to be removed depending on the severity of infestation.

Chemical Control: Outbreaks are suppressed first through the use of copper-containing treatments applied during the dormant period. The antibiotic streptomycin (Agrimycin) is also recommended for use during the bloom period when applied at a rate of 0.20 lb. a.i./acre. Effective insect control, especially of sucking insects such as PLH also helps to reduce the spread of fire blight.

Biological Control: None that are commercially effective.

Cultural Control: Orchard production systems that promote overall tree health while discouraging excessive vegetative growth will reduce the likelihood of late season infection. Although none of the presently available cultivars are resistant to fire blight, consideration should be given to less susceptible scion and rootstocks when establishing new plantings.

Botryosphaeria Rots--4
Black Rot, B. obtusa (Schwein.) Shoemaker
White Rot or Bot Rot, B. dothidea (Schwein.) Shoemaker

Both black and white rot are fungal diseases that may cause serious losses if favorable conditions are present. Infections result in a firm brown rot, primarily at the calyx end of the fruit. Infection commonly occurs at the time of injury, but can occur regardless of injury throughout the growing season. Although there are slight variations in susceptibility to this disease, no cultivars are completely resistant to the types of Botryosphaeria rot. Chemical and cultural controls are of equal importance to the effective management of this disease.

Monitoring: Periodical examinations of orchard blocks will be beneficial in locating infected areas. If frogeye leafspots (black rot) are discovered, an inoculum source is within close proximity. Depending on the stage of development, the inoculum source may be removed and destroyed. If this is not possible, the area should be tagged for attention during the dormant period.

Chemical Control: Fungicides should be applied from bloom through harvest to protect against both the black and the white rot infections.

• benzimidazoles-Benlate 50W (benomyl)-PHI-14 days-can be sprayed in combination with both captan and ziram at a rate of 0.25-0.38 lb. a.i./acre. Topsin-M 70W (thiophanate-methyl)-PHI-0 days-is applied similarly at a rate of 0.35-0.44 lb. a.i./acre. Use of this type of control is recommended from the third cover spray until harvest.
• captan (Captan 50W)-PHI-0 days. Applied at a rate of 3.25-4.0 lb. a.i./acre. REI-96 hours.
• ziram (Ziram 76DF)-PHI-14 days. Applied at a rate of 4.9-6.0 lb. a.i./acre. REI-48 hours.

Biological Control: None that are commercially effective.

Cultural Control: Although cultural practices will not completely control Botryosphaeria rot, they are a critical part of the overall disease management. Practices include pruning and removal of all dead wood, cankers and fire blighted shoots, which may serve as future sources of inoculum, and proper disposal of current-season prunings. Irrigation to limit tree stress may also ward off serious infections.

Bitter Rot, Colletotrichum spp.--5

The bitter rot fungus begins as a small, light brown, circular lesion that enlarges to result in a dark brown saucer-shaped depression on the apple surface. Weather conditions, such as warm rainy periods increase the rate of fruit infection by facilitating spore formation and transfer. Additional phases of the disease include leaf spot and cankers, but these are rare in comparison with fruit infection. Apple cultivars do not vary greatly in susceptibility and outbreaks can be difficult to control given the restricted use of EBDC fungicides.

Monitoring: Fruit may be observed beginning at mid-season and continuing through preharvest for evidence of infection. Although control is difficult to achieve once the disease is established infected areas can be examined for possible sources of inoculum.

Chemical Control: Fungicide application should begin at petal fall and continue at 10-14 day intervals through harvest. EBDC fungicides are useful supplements for management of bitter rot up to 77 days PHI.

• captan (Captan 50W)-PHI-0 days. Applied at a rate of 3.25-4.0 lb. a.i./acre. REI-96 hours.
• ziram (Ziram 76DF)-PHI-14 days. Applied at a rate of 4.9-6.0 lb. a.i./acre. REI-48 hours.

Biological Control: None that are commercially effective.

Cultural Control: Mummified fruits, dead prunings, winter-injured wood, and old and fire blighted cankers should be removed from the orchard, if possible, to eliminate subsequent disease problems

Sooty Blotch and Fly Speck--6

The sooty blotch disease complex is caused by a number of fungi, including Peltaster fructicola Johnson, Sutton & Hodges, Leptodontidum elaitus (G. Mangenot) De Hood, Geastrumia polystigmatis Batista & Farr and others species, while fly speck is Zygophiala jamaicensis E. Mason. Both are surface blemish diseases that commonly appear together on apple fruit in late summer and fall. Under moist, humid conditions losses resulting from sooty blotch and fly speck may be as high as 25%, even in orchards treated with fungicides. Losses are attributed to downgrading of the fruit from fresh market to processing or juice grades based on poor appearance.

Monitoring: Orchards can be examined during the mid-season for evidence of sooty blotch or fly speck infection. Presence of these diseases is a good indicator that fungicide surface residues are lacking or very low, and signals potential need for treatment to control these diseases or other decay producing fungal pathogens.

• benzimidazoles-Benlate 50W (benomyl)-PHI-14 days-can be sprayed in combination with captan, ziram or both at a rate of 0.25-0.38 lb. a.i./acre. Topsin-M 70W (thiophanate-methyl)-PHI-0 days-is applied in the same manner at a rate of 0.35-0.44 lb. a.i./acre.
• captan (Captan 50W)-PHI-0 days. Mixed with the benzimidazoles at a rate of 1.5-2.0 lb. a.i./acre. REI-96 hours.
• ziram (Ziram 76DF)-PHI-14 days. Mixed with the benzimidazoles at a rate of 2.3-3.0 lb. a.i./acre. REI-48 hours.

Biological Control: None that are commercially effective.

Cultural Control: Pruning to open up the tree canopy and thinning to separate fruit clusters may provide control of sooty blotch and fly speck by improving air flow and increasing drying during periods of heavy dew or rain. These practices will also allow for better spray coverage and improved fruit quality.

Rust Diseases--7

There are several rust diseases that can infect apples within the Mid-Atlantic region. These include (1) Cedar-Apple Rust, Gymnosporangium juniperi-viginianae, (2) Hawthorn Rust, G. globosum, and (3) Quince Rust, G. clavipes.. Cedar-apple rust causes the most significant damage from year to year, although the other two species may become problematic depending upon availability of alternate hosts and environmental conditions. The fungi producing these diseases affect the leaves and fruit of most cultivars; the Delicious cultivar is resistant to cedar-apple rust but very susceptible to quince rust. Susceptible cultivars may sustain reductions in crop size and value, as well as severe defoliation.

Monitoring: Monitoring in the case of rust diseases serves to pinpoint fungicide selection and timing weaknesses in the control program based on temperature and duration of wettness.

Chemical Control: Fungicides to control rust diseases are applied periodically from the pink stage of bud development through third cover spray to protect the emerging leaves and developing fruit. Typically, sterol-inhibiting fungicides (SIF) are utilized in conjunction with a protectant such as ziram or an EBDC fungicide. The recommended SIFs include myclobutanil (Nova 40W), fenarimol (Rubigan 1E) and triadimefon (Bayleton 50DF) and are applied at fairly low rates depending on the formulation. EBDC fungicides (mancozeb, metiram and ziram) are applied at rates of 2.3, 2.4 and 4.9 lb. a.i./acre, respectively.

Biological Control: None that are commercially effective.

Cultural Control: Removal of cedars located within a 2 mile radius of the orchard interrupts the life cycle of the fungus and allows for easier chemical control. Removing all the cedars within 4 to 5 miles of any given orchard can provide complete control.

Alternaria Leaf Blotch, Alternaria mali Roberts--8

In the late 1980’s, alternaria leaf blotch was recognized as a serious problem in North Carolina. Within five years, the disease had spread to counties in southern and central Virginia. With the continued spread, Delicious and Delicious-related cultivars are at the highest risk for damage. Symptoms include spotted leaves and eventual defoliation in severe cases. The most serious economic effect is the indirect effects on fruit drop, flavor and color.

Monitoring: No monitoring techniques in use at present.

Chemical Control: Currently, no fungicides are labeled for control of this disease. However, given the synergistic relationship between Alternaria leaf blotch and ERMs, mite control is critical.

Biological Control: None that are commercially effective.

Cultural Control: None that are commercially effective.

Phytophthora Root, Crown, and Collar Rot, Phytophthora spp.--9

Phytophthora root, crown and collar rots are common on fruit trees throughout the world. In severe cases, necrotic lesions on the roots, collar and crown tissues eventually girdle the tree and cause death. Virginia growers may lose up to 15% of the trees in some orchard areas.

Monitoring: Trees (3-5 years old) grown on susceptible rootstock should be observed for characteristic collar rot symptoms such as delayed bud break, leaf and bark discoloration, and twig dieback of the scion. The rootstock of affected trees should be examined more carefully for reddish-brown, water-soaked areas of necrotic tissue on the lower tree trunk. Larger roots nearer the surface may show similar symptoms. Infected trees should be marked for treatment or removal depending on infection severity.

Chemical Control: The fungicides mefenoxam (Ridomil Gold), fosetyl-Al (Aliette) and some coppers are registered for the control of Phytophthora root diseases, however they should be used only as a preventative measure and not as a substitute for good site preparation and the use of roots.

Biological Control: None that are commercially effective.

Cultural Control: Given the number of Phytophthora species that cause root, crown, and collar rot, it is difficult to make absolute statements about the relative susceptibility of different rootstocks to these diseases. Most often Phytopththora collar rot is found on trees propagated on size-controlling rootstocks and trees planted in poorly drained soils. Avoidance of these along with fungicidal control should result in effective management of the disease.

Brooks Fruit Spot of Apple, Mycosphaerella pomi (Pass.) Lindau--10

Irregular, slightly sunken lesions typically on the calyx end of apples characterize Brooks fruit spot, also known as Phoma fruit spot. In well-sprayed orchards this disease is rarely a problem, however severe losses may result if trees are not pruned or treatment applications are spaced far apart or not completed. Certain cultivars are more susceptible than others to Brooks fruit spot.

Monitoring: Orchard monitoring is useful to improve recognition and management in subsequent years; however once symptoms are recognized control is impossible.

Chemical Control: Routine fungicide applications normally control this disease. Applications begin during the second cover spray and continue until harvest, at no less than 14 day intervals.

• benzimidazoles-Benlate 50W (benomyl)-PHI-14 days-can be sprayed in combination with captan, ziram or both at a rate of 0.25-0.38 lb. a.i./acre. Topsin-M 70W (thiophanate-methyl)-PHI-0 days-is applied in the same manner at a rate of 0.35-0.44 lb. a.i./acre.
• captan (Captan 50W)-PHI-0 days. Mixed with the benzimidazoles at a rate of 1.5-2.0 lb. a.i./acre. REI-96 hours.
• ziram (Ziram 76DF)-PHI-14 days. Mixed with the benzimidazoles at a rate of 2.3-3.0 lb. a.i./acre. REI-48 hours.

Biological Control: None that are commercially effective.

Cultural Control: None that are commercially effective.

Effectiveness of Apple Fungicides:

E = excellent; generally good disease control under heavy disease pressure; G = good; good control under moderate disease pressure; F = fair; fair control under moderate disease pressure; S = slight; some control under light disease pressure; N = none; little or no effect on indicated disease; (?) = Information lacking or (-) not applicable.

Although nematode problems are not encountered frequently within Virginia, yearly sampling is recommended. Failure to reduce high population densities of nematodes will result in poor orchard vigor, as well as a decline in productivity, and life span (3). This may be due to root stunting/death or secondary infections caused by nematode feeding. Nematode pests of apple include species of Meloidogyne (root-knot), Pratylenchus (root-lesion), and Xiphinema (dagger) (10). No single practice will eliminate nematode problems from any particular site however; chances for control are greater prior to planting. Once trees are established, there are no effective methods for nematode control. Nonfumigant nematicides may be used, but usually result in limited success.

Monitoring: Properly collected soil samples will allow for accurate estimations of the number of nematodes present within a given area. Population size is usually indicative of the severity of damage that might be caused by nematodes. Techniques for subsampling can be found in the ‘Nematode Management’ section of the 1999 Spray Bulletin for Commercial Tree Fruit Growers (VA, WV and MD Cooperative Extension)(3).

Chemical Control: Preplant soil fumigation and post-plant nonfumigant nematicides can provide effective control against the Pratylenchus and Xiphinema spp. of nematodes. However, no single method of control will eliminate nematode related problems completely.

• 1,3-dichloropropene (Telone II)-Nematicidal fumigant applied at a rate of 27.0-54.0 gal./acre for preplant control of nematodes. REI-5 days.
• 1,3-dichloropropene + chloropicrin (Telone C-17)-Broadspectrum fumigant applied at a rate of 30.0-60.0 gal./acre for preplant control of nematodes, other soil-borne diseases and weeds. REI-5 days.
• fenamiphos (Nemacur 3)-PHI-72 days. Only chemical control agent labeled for use in established apple orchards. Should be applied in a band beneath the drip line of the tree at a rate of 1.5-3.0 gal./acre. May also be applied via low-pressure irrigation systems, not exceeding six treatments per year. REI-48 hours.
• metam-sodium (Vapam)-Broadspectrum fumigant applied at a rate of 40.0-80.0 gal./acre for preplant control of nematodes, other soil-borne diseases and weeds.
• oxamyl (Vydate L)-PHI-14 days. Carbamate insecticide-acaricide-nematicide applied at a rate of 2.0-4.0 pt./100 gal. dilute directly to the foliage when non-bearing trees reach full leaf and then at subsequent intervals, not exceeding 4 treatments per growing season. Spray is absorbed and moves systemically through the plant to the roots. REI-48 hours.

Biological Control: None that are commercially effective.

Cultural Control: Planting apple trees in sites which have never been occupied by fruit trees or which have no prior history of nematode presence will reduce the chances for nematode damage. If that is not an option, removal of old apple roots prior to replanting, along with preplanting select species that serve as poor hosts may reduce the effects of nematodes in newly established orchards. Nematode-free rootstocks may also provide defense against the Meloidogyne spp. of nematode, while TmRSV (tomato ring spot virus)-resistant rootstocks will protect against Xiphinema infestations and any other subsequent diseases transferred by this species (10). Techniques such as cover cropping to improve soil structure, along with sound orchard management practices (fertilization, soil pH, etc.) and control of broadleaf weeds can reduce the effects of nematode feeding. Avoid immediate replanting of areas previously used for fruit production.

Portions of this section were adapted from the herbicide recommendations as listed in the 1999 Spray Bulletin for Commercial Tree Fruit Growers (VA, WV and MD Cooperative Extension) (3).

Overall tree growth, survival and productivity may be greatly reduced by the presence of weeds within the planted row. This is especially true of young trees as a result of competition for water, nutrients and space. In addition, both grasses and broadleaf weeds harbor harmful pests, enhance the likelihood of disease and increase tree injury due to mechanized procedures, such as mowing and cultivation (3). Individual weed species may create other management problems given their specific nature and effects within the orchard. The best method of controlling weeds involves the establishment and maintenance of continuous weed-free zones beneath the tree canopy that alternate with permanent grass sod in the alleyways. Preemergence, postemergence and/or a combination of pre- and postemergence herbicides can be used to develop the weed-free zone. Herbicide selection is primarily based on the problem weeds present and the stage of tree growth. Factors such as soil type and moisture content may also be important in determining preemergence herbicide rates as they relate to movement of a particular chemical through the soil profile. Initial rainfall is necessary for activation, however frequent rainfall may cause the herbicide to leach away from the zone of seed germination, rendering it ineffective. Postemergence herbicide treatments may occasionally be needed to control broadleaf weeds in the grass sod or non-planted strips within the orchard.

The following list contains the most troublesome weeds found in Virginia apple orchards (11):

• Annual Morningglory

• Bindweed species

• Dandelion

• Horsenettle

• Japanese Honeysuckle

• Johnsongrass

• Plantain species

• Poison Ivy

• Pokeweed

• Tall Fescue

• Virginia Creeper

• Wild Blackberries, Dewberries and other Bramble species (Rubus)

Monitoring: No monitoring techniques in use at present.

Chemical Control:

PREEMERGENCE HERBICIDES:

• diuron (Karmex DF)-PHI-0 days. Formulated as a dry flowable. Applied once per season to the orchard floor, prior to fruit set (early spring), at a rate of 3.2 lb. a.i./acre for good to excellent control of most annual weed species. Diuron combined with a contact herbicide provides consistent control of emerged weeds as well. Partial control of many non-woody perennials around trees established at least two years may be achieved by mixing diuron (0.8-1.6 lb. a.i./acre) and terbacil (0.8-1.6 lb. a.i./acre). Treated areas should not be re-cropped within two years following the last application. REI-12 hours.
• napropamide (Devrinol 50 DF)-PHI-0 days.. Formulated as a dry flowable and applied once per season at a rate of 4.0 lb. a.i./acre. Application to the soil surface occurs in the fall through early spring prior to weed emergence. Spring treatment requires rainfall or irrigation within 24 hours.. Safe for use on newly planted and well established trees. Additional herbicides may be paired with napropamide for improved control of annual broadleaf weeds. REI-12 hours.
• norflurazon (Solicam DF)-PHI-0 days. Formulated as a dry flowable for preemergence control of annual grasses and certain broadleaf weeds. Recommended for use on newly transplanted and established apple trees. Applied by ground at a rate of 2.0-4.0 lb. a.i./acre one time during the growing season. Combinations with other pre-and postemergence herbicides results in improved control of annual broadleaf weeds and emerged perennials, respectively. REI-12 hours.
• oryzalin (Surflan A.S.)-PHI-0 days. Formulated as an aqueous solution for long-term (6-8 months) control of annual grass and broadleaf weed emergence when applied at a rate of 2.0-6.0 lb. a.i./acre. Lower rates are use or short-term control (4 months). In each case, one application occurs by ground during the growing season on both newly transplanted and well established trees. For control of many more broadleaf weeds, oryzalin may be mixed with diuron, simazine or terbacil. REI-12 hours.
• oxyfluorfen (Goal 2XL)-Formulated as an emulsifiable concentrate and registered for dormant or delayed-dormant application of bearing or non-bearing trees at a rate of 0.5-2.0 lb. a.i./acre. Controls certain annual grasses and most broadleaf weeds but can be improved when combined with other preemergence herbicides. Although oxyfluorfen controls small seedlings of annual weeds, it should be combined with an additional postemergence herbicide (i.e. glyphosate, glufosinate, etc.) to increase efficacy on emerged species. REI-24 days.
• pronamide (Kerb 50W)-PHI-0 days. Formulated as a wettable powder for use on annual (1.0-2.0 lb. a.i./acre) and perennial (2.0-4.0 lb. a.i./acre) grasses. Recommended for fall applications in orchards to control cool-season grasses perennial grasses and certain other weeds. However, pronamide does not provide full-season coverage and will, therefore, need to be used in conjunction with other herbicides. REI-12 hours.
• simazine (Princep) (Caliber90 4L)-PHI-0 days. Formulated as a water dispersible granule and as a liquid. Recommended for use around young trees that have been established one full year. Found to be effective on annual broadleaf weeds (before emergence) when applied at a rate of 2.0-4.0 lb. a.i./acre. Application can occur anytime by ground, one time per growing season. Should not be used on sandy or gravelly soils. Although simazine alone does not kill emerged weeds, it is effective when paired with glyphosate or paraquat. A reduced rate of simazine may be necessary when paired with other pre-emergent herbicides. REI-12 hours.
• terbacil (Sinbar)-PHI-0 days. Formulated as a wettable powder. Recommended for use in trees that have been established at least 3 years for good control of annual and some perennial weeds. Applied once either in the spring or after the harvest in the fall (before weeds emerge or during early seedling stage) at a rate of 1.6-3.2 lb. a.i./acre. Terbacil can also be used to control most annual and some perennial weeds in trees established two full years when applied one time during the year in combination with diuron at a rate of 0.8-1.6 lb. a.i./acre. Should not be used on sandy or gravelly soils or on soils low in organic matter (less than 1%). Treated areas should not be re-cropped within two years following application. REI-12 hours.

POSTEMERGENCE HERBICIDES:

• 2,4-D amine (Weedar 64) (Hi-Dep)-PHI-0 days. Formulated as a liquid for effective control of broadleaf weeds. May be applied in combination with other postemergence herbicides (glyphosate, sethoxydim) for improved control of troublesome weeds. Sprayed directly, one or two times per season, on young actively growing weeds at a rate of 1.5 lb. a.i./acre. Commonly used in the permanent sod strips to eliminate or suppress blooming weeds. Control of blooming weeds, especially dandelions is imperative given their competition with apple blossoms for pollinators, particularly honey bees. Research suggests that other insecticide residues found on the grass may inadvertently kill the bees interested in the blooming weeds. No other herbicides currently registered for use in apple orchards can function in the same capacity as 2,4-D in relation to control of blooming weeds. REI-48 hours.
• fluazifop-p-butyl (Fusilade DX)-PHI-365 days. Formulated as an emulsifiable concentrate for control of emerged annual and perennial grasses in nonbearing apples. Applied directly on actively growing annual grasses at a rate of 0.25-0.37 lb. a.i./acre. Fruit may not be harvested for one full year after application. Fluazifop-p-butyl is a systemic herbicide that affects only grasses and leaves no soil residue. REI-12 hours.
• glufosinate (Rely)-PHI-14 days. Formulated as a liquid herbicide labeled for use only on apples. Glufosinate is a non-selective herbicide applied directly at a rate of 0.75-1.5 lb. a.i./acre to annual and perennial weeds at ground level. Rate may very depending on the height of the weeds. Thorough coverage is necessary for good control. Repeat treatments may be required within a growing season, especially for perennial weeds. REI-12 hours.
• glyphosate (RoundUp Ultra)-PHI-14 days. The most broadspectrum herbicide available to growers. Formulated as a liquid and recommended for excellent control of emerged annual and perennial weeds. Should be applied at a rate of 1.5-5.0 lb. a.i./acre for general control. Higher rates, not exceeding 5.0 lb. a.i./acre, will be needed for troublesome perennials and hard to kill problem weeds. Treatments for perennial weeds should be made to the ground after the weed species flowers, sets fruit, or has mature foliage. REI-12 hours.
• paraquat (Gramoxone Extra)-PHI-0 days. Formulated as a liquid and used as a contact herbicide for most weed species, particularly annual broadleaf and grass weeds. Repeated applications of 0.6-0.9 lb. a.i./acre will be necessary to give sustained control. Most effective if sprayed directly on the weeds and grasses when they are succulent and the new growth is from 1-6 inches high. Safe for use around young trees and also for mature trees in the late summer. REI-12-48 hours.

Biological Control: None that are commercially effective.

Cultural Control: In some orchards, both the grass alleyways (Kentucky-31 tall fescue) and the vegetation beneath the tree canopy are maintained solely by mowing (12). However, mowing of row middles often occurs in addition to an effective herbicide program. Cultivation may also serve as a form of weed control, sometimes in conjunction with herbicide application.

Table 9. Relative Effectiveness of Preemergence Herbicides in Tree Fruits

(E=excellent; G=good; F=fair; P=poor; N=none)

Table 10. Relative Effectiveness of Postemergence Herbicides in Tree Fruits

(E=excellent; G=good; F=fair; P=poor; N=none)

Plant Growth Regulators

Recommendations were taken from the ‘Programs for Apples’ section found in the 1999 Spray Bulletin for Commercial Tree Fruit Growers (VA, WV and MD Cooperative Extension) (3).

Plant growth regulators modify the growth and development of fruit trees either by separately influencing vegetative growth or fruiting parts, or by effecting a combination of both. A variety of factors such as species, stage of development and weather can effect the performance of plant growth regulators within the orchard environment. Dosage is also of high concern when applying growth regulators, with inadequate levels yielding poor results and excessive levels causing severe tree damage.

The following list includes the purposes for which plant growth regulators may be used within commercial apple orchards in Virginia:

1. Crop thinning (improving fruit size)
2. Defruiting young trees
3. Promoting flower initiation for the following year
4. Controlling/promoting vegetative growth
5. Improving fruit shape
6. Improving fruit finish (preventing russetting and cracking)
7. Stimulation of coloring and ripening
8. Controlling preharvest drop of apples

Through the use of the various plant growth regulators listed above, Virginia apple growers have the tools with which to improve the overall vigor and productivity of their apple trees and, therefore, to ensure consistent crop production from one year to the next. This is a very cost-effective method of managing an orchard with benefits being felt at both the grower and consumer levels. For example, one of the primary reasons for the use of plant growth regulators is to control the amount of fruit on any given tree. This technique not only ensures bloom the following year and improves apple quality (size, color, sugar level, etc.), but it also allows for increased pesticide efficacy within pest control programs.

In Virginia growers maintain very active thinning programs, generally applying more than one application of a thinning agent per block per growing season. Typically, the second application involves a different chemistry than the first. In this way, all six of the growth regulators registered for thinning within this state play an intricate role in the overall productiveness of the thinning program. Removal of any of these compounds will limit program effectiveness, especially when considering timing of the application, size of the fruit to be thinned and the variety (cultivar) of fruit treated. Ethephon, for example, is the only chemical available that has been shown to adequately thin large fruit (13–30 mm), while NAD is effective only if sprayed on smaller fruit (up to 10 mm) starting at petal fall. In addition to this type of specificity, most of the non-insecticidal thinning agents work only when applied to certain varieties of apple. Therefore, elimination of key thinning compounds such as carbaryl and oxamyl, both of which are classed with the carbamate pesticides, will reduce the ability of growers to stabilize crop production and also to provide consumers with high quality fruit. Both carbaryl and oxamyl provide consistent results over a wide range of environmental conditions and also sizes and varieties of fruit. This same consistency has not been achieved through the use of the other registered thinning agents, making the carbamate compounds irreplaceable in this capacity. The thinning potential of carbaryl and oxamyl may be improved if combined with compounds such as Accel and NAA. Use of the latter two chemicals individually has not usually provided adequate results. Hand-thinning of apples, by itself, is not usually economically practical.

• aminovinylglycin-AVG (Retain)-PHI-28 days. Retain is used primarily to provide preharvest drop control, however, delayed loss of fruit firmness and starch and/or an increase in fruit diameter may also result due to the maintenance of fruit on the tree. Should be applied in combination with a silicon surfactant 4 weeks prior to anticipated harvest. Rates are dependent upon variety.
• auxins (NAA) (NAD)

• carbaryl (Sevin)-PHI-1 day. Sevin is of central importance in many orchards and is often used separately or in combination with other thinning agents included in this list. Should be applied at a universal rate of 1.0-3.0 lb. a.i./acre; effective beginning at petal fall through 14 mm. Sevin has insecticidal as well as growth regulator properties. REI-12 hours.
• cytokinin and gibberellins (Accel) (Promalin)

• gibberellins (Provide)-If used to reduce russetting, should be applied at a rate of 10.0-13.0 oz./acre 2-4 times starting at petal fall and continuing in 7 day intervals. For control of fruit cracking, should be applied at a rate of 1.0–2.0 pt./acre beginning in mid June and continuing at 2 week intervals for a total of 3-6 treatments. In both cases, gibberellin should be used in a preventative manner.
• ethephon (Ethrel)-Applied as a thinning agent at an average rate of 200 to 400 ppm a.i. in 200-250 gal./acre. Higher concentrations may be used depending on the variety treated, with 450 gal./acre being the maximum allowable concentration. May also be used to stimulate color and ripening when used 1-2 weeks prior to the normal harvest period. Not often used in this capacity given that ethephon can also cause early and severe fruit drop.
• oxamyl (Vydate)-PHI-14 days. Carbamate insecticide-acaricide-nematicide, applied at a rate of 0.5–1.0 lb. a.i. per acre between petal fall and the time at which fruit reaches 14 mm. Not as effective of a thinning agent if used on apples greater than 14 mm. Do not apply with oil. REI-48 hours.

Portions of this section were adapted from the recommendations for wildlife control found in the 1999 Spray Bulletin for Commercial Tree Fruit Growers (VA, WV and MD Cooperative Extension) (3).

Pests are listed in order of importance to the production of apples in Virginia

Meadow Vole, Microtus pennsylvanicus
Pine Vole, Microtus pinetorum

Both the meadow vole and the pine vole may cause devastating damage within apple orchards in Virginia. Damage results primarily from vole feeding either at the base of a tree that causes girdling of the cambium, or within the root system, which weakens the tree. Trunk damage above the soil line is most often associated with the meadow vole, while weakened or girdled roots result from pine vole feeding. Feeding usually takes place during the winter months when other food sources such as grasses are in limited supply. The greatest injury due to these pests arises when the number of voles is high, however, the economic threshold for damage occurs at very low population levels.

Monitoring: The presence of meadow voles is easily detected by a system of surface runways, while pine vole activity is more difficult to detect given their underground habitat. Tiny elongated tooth marks found on apples dropped from the tree are indicative of both types of vole. The apple indexing method uses this latter type of injury to monitor vole population size and distribution. Apples (with 1-inch slices cut off the side) are placed in active runways and checked for teeth marks 24 hours after placement. Weighing the apples prior to placement in the runs will allow for a more exact measure of vole abundance (one meadow vole consumes 20.0 grams of apple in 24 hours and a pine vole consumes about13 grams) (12). Apple indexing can also be used to evaluate various control techniques.

Chemical Control: There are several rodenticides labeled for control of voles in Virginia. The method (hand-placed baiting or broadcasting) depends on the label requirements, grower needs and on the type of groundcover present. The chemicals listed below are registered only for use following harvest and during the dormant season. Although there have been no reported cases of resistance to these chemicals, care should be taken to avoid the continuous use of any one formulation.

• chlorophacinone (Parapel)(Rozol)-Hand placed baits of this compound should be applied at a rate of 10.0 lb. per acre for both types of voles and they should be broadcast at a rate of 20.0 lb. per acre for pine voles and 15.0 lb. per acre for meadow voles. Rates lower than this may not allow for the lethal dose required for killing these pests. Chlorophacinone, which acts as an anticoagulant, is more effective against pine voles than meadow voles.
• diphacinone (Ramik-Brown)-Available in pelleted form, diphacinone also acts as an anticoagulant. It should be hand-placed or broadcast at a rate of 10.0 + 10.0 lb. per acre at 20-40 day intervals for both meadow and pine voles.
• zinc-phosphide (Bait AG)-Zinc phosphide hand-placed grain baits should be applied at a rate of 2.0 lb. per acre and broadcast at a rate of 10.0 lb. per acre for control of both meadow and pine voles. Broadcast applications require at least 3 good days of weather following treatment. Apple baits coated with 1.0 tsp./qt. of zinc-phosphide and placed under covers and in holes are more effective than grain baits for vole control. However, if populations remain high, this chemical should not be used as a repeat bait due to bait shyness as a result of taste.

Biological Control: Natural predators of voles include foxes hawks, house cats, opossums, owls, raccoons, shrikes, snakes, weasels. However, this type of control is rarely considered to be of commercial importance within the orchard environment. Vole predators can help to manage populations and care should be taken to encourage their presence in areas of vole activity.

Cultural Control: Several practical approaches are available for controlling voles within orchards. These include habitat modification, exclusion, and trapping. Habitat modification is one of the best long-term methods for controlling vole populations. Eliminating grasses and other groundcover beneath tree canopies discourages voles from living near the bases of trees. Repeated mowing of the vegetative strips/orchard rows limits food sources and also helps to expose the voles to potential predators. Exclusion refers to the use of hardware cloth barriers or tree guards to deter vole feeding around tree trunks. The exclusion method is effective for meadow vole management, but does not work particularly well to control pine voles.. Of the possible cultural controls, trapping is the least efficient, however, it is an effective and safe way of inhibiting voles in specified areas or small orchards.

White-tailed Deer, Odocoileus virginianus

One of the most well known mammals in North America, the white-tailed deer is commonly found in commercial apple orchards in Virginia. Deer can cause damage either by browsing on the dormant or terminal buds in the winter months, "rubbing" tree trunks and limbs during the spring and summer, and feeding on mature fruit in the fall.

Monitoring: No monitoring techniques in use at present.

Chemical Control: Taste and odor repellents are available to deter deer presence within an orchard; with effectiveness depending on population size, other deer food sources and weather. These chemicals may become expensive if repeated applications are necessary, (i.e. following every rain event). Repellents are generally applied during the dormant season either as aerial, ground or spot treatment application. In addition to the products listed below, both deodorant soap and human hair have been used to ward off deer, especially within young trees.

• capsaicin (Hot Sauce Animal Repellant)-Applied as an aerial spray during the dormant period. Must be used in combination with Vapoguard (2.0 qt./gal. of water) at a rate of 6.0-8.0 oz./gal. of water. Both mixtures should be added to water to obtain a total volume of 100 gal.
• denatonium saccharide (Ro-pel)-Should be applied only during periods of tree dormancy. Do not dilute; apply directly from bottle with a paintbrush or course sprayer to areas commonly fed upon by deer (i.e. twigs and trunks).
• hinder (Hinder)-Active ingredients (13.8%) include ammonium salts of C8-18 and C18’ fatty acids, ammonium soaps of fatty acids, and phenol, 2,4-dichloro-benzenesulfonate. May be applied during the growing season or dormant period at a rate of 3.0-5.0 gal./100 gal. of water (ground) or 3.0-5.0 gal/5-10 gal. of water/acre (aerial) to deter deer feeding.
• putrescent whole egg solids (Deer Away Big Game Repellent)-Should be applied directly with a coarse sprayer to areas targeted for deer feeding.. Two part product that when mixed results in a 20 gal. treatment. Apply only during the dormant period.
• thiram (Thiram 42-S)-Can be applied either during the growing season or dormant periods, however, treatment should not occur within one year of expected harvest. If applied as a foliar spray, 1.0 qt. Thiram 42-S should be combined with 1.0 pt. latex sticker in 7.0 qt. of water. Dormant apple twigs and tree trunks should receive 2.0 gal. combined with 1.0 gal. sticker in 100 gal. of water. Fruit can not be harvested for a full year following repellent treatment. Chew-not contains 20% of the active ingredient, thiram and is formulated as a ready to use product.

Biological Control: None that are commercially effective.

Cultural Control: Hunting licenses or special permits may be obtained to decrease population size. Trained dogs confined by invisible fencing may also be used to reduce the presence of deer within an orchard. Various forms of electric and non-electric fencing are available for prohibiting deer entry into orchards. Combinations of these control techniques are usually more effective than any form used alone.

Rabbit, Sylvilagus floridanus

Rabbits may create serious problems for orchardists during the late fall and winter as a result of bark chewing and feeding on scaffold limbs of young trees (< 5 years old). The worst type of damage results from feeding at the base of the tree resulting in girdling of the cambium and possible cambium death. If caught in a timely manner, injury to the girdled area may be repaired by bee’s wax or a water-based dressing.

Monitoring: No monitoring techniques in use at present.

Chemical Control: Protection against damage caused by rabbits may be conferred through the use of chemical repellents applied to tree trunks and other areas where feeding occurs.. As with deer repellant, effectiveness depends on population size/pressure, timing and also weather, particularly rainfall. Products used as rabbit repellents are similar to those applied for deer (see above), however, rates may be slightly less in some cases.

Biological Control: Some natural predators of rabbits include barn owls, coyotes, foxes, hawks, opossums, and weasels. However, within orchards where rabbit populations have reached damaging levels, predators have not solely maintained effective control.

Cultural Control: Tree guards are both economical and effective in preventing rabbit access to commercial orchards, especially when used in conjunction with repellents. Additional control may be facilitated through hunting and/or the removal of potential habitats such as brush piles and heavy weeds.

Woodchuck/Groundhog, Marmota monax

The burrowing nature and vegetative feeding habits of the woodchuck may result in tree damage within the orchard setting. Direct injury to the roots, trunks and scaffold limbs is common, especially among young or newly planted trees. Indirectly, open woodchuck burrows may be hazardous to humans working within the orchard while walking or operating farming equipment.

Monitoring: No monitoring techniques in use at present.

Chemical Control: Chemical fumigation of the animals within the burrows is the most practical control method available. Currently, phostoxin™ is recommended in the early spring for woodchuck control within orchards in Virginia, although it is classified as restricted. Aluminum phosphide is the active ingredient of phostoxin™.. Phosphine gas is evolved once this material comes in contact with moisture. Care should be taken when storing this compound.

• Aluminum phosphide-Formulated in combination with various waxes, 2-4 pellets should be placed in an active burrow and all burrow openings sealed. Lower rates may be used in small burrow systems or when moist conditions prevail. Conversely, higher rates may be needed for larger burrows or when soil moisture is low. Additional treatments should be applied 1-2 days after initial treatment if burrows are reopened.

Biological Control: None that are commercially effective.

Cultural Control: Hunting and/or trapping are both effective means of controlling woodchuck populations, however, they may not be practical within large-scale orchard operations.

Beaver, Castor canadensis

Orchards that are planted near waterways may be at risk for severe damage as a result of beaver inhabitancy. Once beavers move into this type of environment, complete devastation of whole trees can occur in a very short period of time.

Monitoring: No monitoring techniques in use at present.

Chemical Control: No specific chemical controls are available to reduce beaver damage within Virginia orchards.

Biological Control: None that are commercially effective.

Cultural Control: Currently trapping and shooting are the most effective ways of avoiding damage due to beaver populations. Fencing may also be an option, although not a very cost efficient alternative.

C&P Press Online Crop Protection Reference
http://www.greenbook.net/free.asp

Mid-Atlantic Regional Fruit Loop
http://www.caf.wvu.edu/kearneysville/fruitloop.html

Office of Pest Management Programs/Pesticide Impact Assessment Program Site
http://ipmwww.ncsu.edu/opmppiap

Virginia Tech Pesticide Programs
http://www.vtpp.ext.vt.edu

Virginia Pesticide Impact Assessment Program
http://www.vtpp.ext.vt.edu/htmldocs/vanapiap.html

Prepared by:
Donna M. Tuckey
Graduate Assistant
Department of Entomology
Virginia Polytechnic Institute & State University
Virginia Tech Pesticide Programs-0409
Blacksburg, VA 24061
Ph: (540)-231-6543
Fax: (540)-231-3057
e-mail: dtuckey@vt.edu

Contacts and Contributors:

Ross E. Byers
Extension Horticulturist, Tree Fruits
Winchester AREC
595 Laurel Grove Road
Winchester, VA 22602
Ph: (540)-869-2560
Fax: (540)-869-0862
e-mail: rossebye@vt.edu

Jeff F. Derr
Extension Specialist, Weed Science
Hampton Roads AREC
1444 Diamond Spring Road
Virginia Beach, VA 23455
Ph: (757)-363-3912
Fax: (757)-363-3950
e-mail: jderr@vt.edu

Rich P. Marini
Extension Horticulturist, Tree Fruits
Virginia Polytechnic Institute & State University
Department of Horticulture-0327
Blacksburg, VA 24061
Ph: (540)-231-5365
Fax: (540)-231-3083
e-mail: marinirp@vt.edu

Doug G. Pfeiffer
Extension Entomologist, Tree Fruits
Virginia Polytechnic Institute & State University
Department of Entomology-0319
Blacksburg, VA 24061
Ph: (540)-231-4183
Fax: (540)-231-9131
e-mail: dgpfeiff@vt.edu

Michael J. Weaver
Extension Pesticide Coordinator
Virginia Polytechnic Institute & State University
Department of Entomology
Virginia Tech Pesticide Programs-0409
Blacksburg, VA 24061
Ph: (540)-231-6543
Fax: (540)-231-3057
e-mail: mweaver@vt.edu

Keith S. Yoder
Extension Pathologist, Tree Fruits
Winchester AREC
595 Laurel Grove Road
Winchester, VA 22602
Ph: (540)-869-2560
Fax: (540)-869-0862
e-mail: ksyoder@vt.edu

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