Crop Profile for Apples in New England

Aphid, Apple
Type of Pest: Insect
Frequency of Occurrence: This pest rarely requires pesticide application.
Damage Caused:  If abundant, they produce large amounts of honeydew which falls onto foliage and fruit. The honeydew serves as an excellent growth medium for black sooty mold fungus, which can mar and discolor the fruit surface.
% Acres Affected: Present in almost all acreage, but rarely reaches pest status due to effective biological control.
Timing of Control: The eggs complete hatch soon after half-inch green. The nymphs and adults are light green with black cornicles. Usually, they do not become abundant until July, and are found primarily on the succulent foliage of water sprouts and growing terminals. The recommended treatment threshold is if checking at least 10 terminals per tree and 10 trees per block reveals that 50% of vegetative terminals are infested AND less than 20% of the infested terminals have biocontrol agents present. Water sprouts should be included in proportion to their presence in the canopy. Another treatment threshold is if   10% of the fruit show staining from aphid excrement (honeydew). While easily washed off, honeydew can lead to growth of sooty mold fungus and interfere with harvest and pick-your-own marketing.
Yield Losses: Minimal.
Regional Differences: None
Cultural Control Practices: Excessive and prolonged vegetative growth can lead to an apple aphid problem. Limit nitrogen fertilization to the level necessary for optimum tree growth. Summer pruning to remove water sprouts can also prevent or reduce problems with apple aphids.
Biological Control Practices: Commercial orchards can tolerate small to moderate populations of the apple aphid, thus there is considerable potential for integrated pest management of this pest.  Several predators destroy apple aphid colonies. Where beneficial species are accounted for in spray decisions, predators typically eliminate the need for chemical control. Syrphid and cecidomyiid fly larvae are the most common aphid predators in New England orchards.
Post-Harvest Control Practices:
Other Issues:

Chemical Controls for Apple Aphid:

Aphid, Rosy Apple
Type of Pest: Insect
Frequency of Occurrence: The RAA will attack all apple varieties, but varieties such as Cortland, Monroe, Rhode Island Greening, Ida Red, and Golden Delicious are particularly susceptible. This pest rarely requires pesticide application.
Damage Caused: RAA feeding causes apple leaves to curl and often turn a bright crimson. Leaf curling normally does not become obvious until about petal fall. Feeding on the leaves of fruit clusters often results in bunching, stunting, and malformation of the fruit, which becomes noticeable as the fruit develops and renders it unmarketable. Honeydew produced by the aphids provides a media for the growth of a sooty mold fungus which can affect the fruit finish.
% Acres Affected: < 5%
Timing of Control: tight cluster to pink; post-petal fall
Yield Losses:
Regional Differences: None
Cultural Control Practices: NA
Biological Control Practices: Although there are several predators or parasites of the RAA, they cannot be relied upon to provide acceptable biological control.
Post-Harvest Control Practices: NA
Other Issues: Postbloom application generally will not prevent fruit damage.

Chemical Controls for Rosy Apple Aphid:

Aphid, Woolly Apple
Type of Pest: Insect
Frequency of Occurrence: This pest rarely requires pesticide application.
Damage Caused: Cottony-white aerial colonies are found most frequently on succulent tissue, such as current season's growth, water sprouts, unhealed pruning wounds, or cankers. Heavy infestations can cause honey dew and sooty mold on the fruit, and galls on the plant parts. Underground colonies may be found throughout the year on the root systems of orchard trees or nursery stock. Severe root infestations can stunt or kill young trees, but usually cause little damage to mature trees. WAA can also transmit perennial apple canker.
% Acres Affected: < 5% with significant populations
Timing of Control: July, when colonies begin to appear in canopy.
Yield Losses:
Regional Differences: None  
Cultural Control Practices: Chemical control of root infestations is not possible; resistant rootstocks provide the only defense against underground infestations. The Malling-Merton (MM) rootstock series was developed to provide resistance to WAA infestation.
Biological Control Practices: The WAA is frequently parasitized by Aphelinus mali, a tiny wasp that is also native to North America. Parasitized aphids appear as black mummies in the colony. A. mali has been successfully introduced to many apple-growing areas of the world, and is providing adequate control of the WAA in several areas. It does not provide sufficient control in commercial orchards in the northeastern United States because of its sensitivity to many commonly used insecticides; however, the wasp is thought to reduce WAA populations in abandoned orchards.
Post-Harvest Control Practices:
Other Issues: Because the woolly apple aphids are somewhat protected by their waxy covering, regular spray programs may not provide adequate control. High volume applications of recommended insecticides may be necessary to penetrate the wax. Failure to control aerial infestations can result in underground infestations on susceptible rootstocks. However, this pest rarely requires pesticide application.

Chemical Controls for Woolly Apple Aphid:

Apple Maggot
Type of Pest: Insect
Frequency of Occurrence: Annually in potentially every block
Damage Caused: Signs of the infestation on the fruit are minute egg punctures in the skin and pitted areas on the surface. In late season varieties, the injury usually appears as corky spots or streaks on the flesh. In varieties ripening during July, August and September, open tunnels may occur. Rot producing organisms follow the maggots causing rapid decay of infested fruit.
% Acres Affected: potential 100%
Timing of Control: July-August 
Yield Losses: >30% if untreated
Regional Differences: None
Cultural Control Practices: removal of wild hosts and abandoned apple trees. Trapping out the AMF has been tried in some orchards, and may be an effective management tool for some growers.
Biological Control Practices: insignificant
Post-Harvest Control Practices: NA
Other Issues:

Chemical Controls for Apple Maggot:

Borers, Dogwood borer and Roundheaded apple tree borer
Type of Pest: Insect
Frequency of Occurrence: Borers are not normally a problem in established orchards where orchard grass and weed growth near the tree trunks is kept in check, close-fitting plastic spiral vole guards are removed at petal fall, and summer insecticide sprays are made for other pests. Dogwood borers seem to be increasing as a pest of dwarf apple orchards, particularly in southern New England. Susceptible scion/rootstock combinations are attractive and very likely to be infested where dogwood borers occur on wild and orchard hosts. Borer damage has increased with increased use of M9 and M26 rootstocks prone to burr knot formation, and are a serious problem in low spray orchards.
Damage caused:  Girdling of trunk, variable weakening of tree including tree death on young trees. Adult borers lay eggs that hatch into bark/wood-tunneling larvae. Burr-knots on rootstocks are particularly attractive to adults as a place to lay eggs. Often, tunneling and damage is concentrated in burr-knots, however, severe infestation with girdling can result in loss of productivity and decline/death of the whole tree. Young trees are most susceptible.
% Acres Affected: < 25% with potential 100% of new plantings with dwarf rootstocks such as M26 and M9
Timing of Control:   June through August for insecticides with short residual control.  Single Lorsban application seems to provide season-long control.
Yield Losses:  Unknown losses due to reduced productivity. Could be from five to 100%, depending on orchard block, tree age, cultivar, and rootstock. Primarily a result of young tree decline or death, thus affecting the long-term productivity of the orchard. Whole orchards of new plantings have been killed. General OP applications relegate borers to secondary pest, but where susceptible rootstocks are planted and insecticide frequency is low, this pest has serious damage potential.
Regional differences: Unknown, but may be more common in Massachusetts, Connecticut, and Rhode Island.
Cultural Control Practices: Planting rootstocks that don't have a tendency to form burr-knots; planting graft union just above ground line; avoid use of solid plastic mouse guards, or at least remove them during the growing season; maintain clean, debris and weed-free area around base of tree.  Removal of vole guards, vegetation control around young trees.
Biological Control Practices: Bird predation contributes to suppression.
Post-Harvest Control Practices: NA
Other Issues: Few sprays are applied specifically against borers in established orchards, but borer control is important in new plantings.  In established plantings borers are controlled by applications against other pests (PC and AM). Loss of OP's would increase the significance of this pest.

Chemical controls for Dogwood borer and Roundhead apple tree borer:

Codling Moth
Type of Pest: Insect
Frequency of Occurrence: Annually in potentially every block
Damage Caused: Larvae may cause "stings", which damage only the surface flesh of the fruit. Deep inner tunneling results in internal breakdown and possible abortion of the fruit.
% Acres Affected: potential 100%
Timing of Control: Key time for monitoring: Bloom through harvest. Degree days (DD), calculated from base 50 degrees Fahrenheit, are accumulated from the date of first sustained moth catch (the biofix). The first spray is applied at 250 DD50 after the biofix. This timing corresponds to a predicted 3% egg hatch. A second spray may be applied 10-14 days later. If pressure is not overly severe, one spray, applied at 360 DD50 after the biofix, is sufficient. A spray for the second generation should be applied 1260 DD50 after the biofix date. If CM pressure is severe, that application should be followed by another one in 10-14 days.
Yield Losses:  
<5%; if untreated losses would be 30-40%. General OP applications have made CM a secondary pest.> Regional Differences: None
Cultural Control Practices: Mating disruption technology has not reached economic efficiency for recommendation for use in New England orchards, especially given the fact that this pest is controlled by applications made against other pests.
Biological Control Practices: Predators and parasites feed on CM, but these natural enemies cannot keep this pest from reaching damaging levels in commercial orchards.
Post-Harvest Control Practices: NA
Other Issues: Few sprays are applied specifically against CM; controlled by applications against other pests (PC and AM). Loss of OP's would make this a significant pest of apples.

Chemical Controls for Codling Moth:

Climbing Cutworms
Type of Pest: Insect
Frequency of Occurrence: rare
Damage Caused: Most injury from climbing cutworms occurs in the spring when they feed on fruit buds or blossoms. The larvae generally feed only on the lower central portion of the tree around the trunk, but under high population pressure, complete limbs or even whole trees may be stripped. Small trees are the most severely affected and abnormal growth can result from heavy defoliation several years in a row. Feeding by cutworms on the foliage or fruit during the fall or summer is rare, but may occur when the variegated cutworm is present.
% Acres Affected:
Timing of Control: April through August, when observed.
Yield Losses: <1%>
Regional Differences: None
Cultural Control Practices: Keeping the ground cover mowed around young trees may reduce the chance of cutworm problems. The best way to monitor is to check buds in the lower center of young trees for signs of first feeding early in the spring and to check the leaf litter around the base of the tree for overwintering larvae. Examine sites on the ground for rolled up larvae (under clods of earth, etc.). The larvae can only be observed feeding in the trees at night. Black light traps readily capture the adults, but because of the many host plant species and similar looking nonpest species, it is usually not an effective way to monitor.
Biological Control Practices:
Post-Harvest Control Practices:
Other Issues: So rare and sporadic that not enough sprays are applied to indicate a preference of materials.

Chemical Controls for Climbing Cutworms:

European Apple Sawfly
Type of Pest: Insect
Frequency of Occurrence: Annually
Damage Caused: The first larval instar commences feeding just below the skin of the fruit, creating a spiral path usually around the calyx end. Should the fruit receive no further injury, this early larval feeding will persist as a scar that is very visible and objectionable at harvest. Following this feeding, the larva usually molts and begins tunneling toward the seed cavity of the fruit or an adjacent fruit. The larva's feeding to the core usually causes the fruit to abort. As the larva feeds internally, it enlarges its exit hole, which is made highly conspicuous by the mass of wet, reddish-brown frass, or insect excrement. The frass may drip on adjacent fruit and leaves, giving them a similarly unsightly appearance. The secondary feeding activity of a single sawfly larva can injure all the fruit in a cluster, causing stress on that fruit to abort or drop during the traditional "June drop" period.
% Acres Affected: potentially 100%
Timing of Control: Early pink-petal fall.
Yield Losses: <5% where controlled.  >30% without control 
Regional Differences: None
Cultural Control Practices: None
Biological Control Practices: None
Post-Harvest Control Practices: None
Other Issues: Insecticide is needed after Petal Fall for plum curculio anyway but timing options are narrowed with EAS.  Application is required right at Petal Fall where EAS pressure is high as indicated by trap captures or block history.  In some cases, prebloom application is also targeted at suppressing EAS.  More of a problem in blocks of mixed cultivars with different Petal Fall timing.

Chemical Controls for European Apple Sawfly:

European Corn Borer
Type of Pest: Insect
Frequency of Occurrence: Rarely reaches pest status.
Damage Caused: ECB larvae sometimes tunnel in current year's shoots, causing them to wilt. The caterpillars, which are light colored with a dark brown head, have also occasionally been found in the fruit. Typically this occurs on lower limbs near groundcover, and in blocks near cornfields.
% Acres Affected: <1%
Timing of Control: June; August when insects or damage noted
Yield Losses: <1%
Regional Differences: None
Cultural Control Practices: Keeping groundcover mowed helps prevent damage.
Biological Control Practices: Many natural parasites of this corn borer, mainly flies and wasps which have been introduced from Europe, exist in areas. Other biological control agents such as ladybird beetles, predaceous mites, and downy woodpeckers have also been responsible for some borer reduction.
Post-Harvest Control Practices: NA
Other Issues: Damage occurs rarely. Usually, regular cover sprays of OP's minimize damage.

Chemical Controls for European Corn Borer: Specific sprays for ECB are extremely rare.

Green Fruitworms
Type of Pest: Insect
Frequency of Occurrence: Sporadic
Damage Caused: Most flower buds and blossoms damaged by GFW larvae abort. Most fruit damaged just prior to and shortly after petal fall also drop prematurely. Some, however, remain at harvest and exhibit deep corky scars and indentations. This injury is indistinguishable at harvest from that caused by the overwintering larvae of the obliquebanded leafroller.
% Acres Affected: <20%
Timing of Control: Since feeding activity begins before bloom, insecticides may be required when buds develop 1/2 inch of new growth (green tissue) and again at petal fall. Fruitworms are usually kept under control with sprays targeting other insect pests on apples.
Yield Losses: <5%><5%
Regional Differences: None
Cultural Control Practices:
Biological Control Practices: None
Post-Harvest Control Practices:
Other Issues:

Chemical Controls for Green Fruitworms:

Leafhopper, Potato
Type of Pest: Insect
Frequency of Occurrence: Sporadically heavy, depending on weather patterns
Damage Caused: The cellular injury caused to the leaf of the various food plants causes a typical "hopperburn." Unlike WLH, PLH prefers young leaves, and consequently is a greater problem on young trees, which have a greater proportion of young leaves on each tree, and continue growing longer into the season. Invasion and resulting damage can occur quickly. The edges of the leaf curl downward, first turning lighter green, then yellow, and finally brown and necrotic. On young trees this may be sufficient to stunt growth. If these leafhoppers are controlled, growth may resume later in the season.
% Acres Affected: <20% 
Timing of Control: Treatments are when adults first appear in young blocks, especially if PLH has been a problem in the area in the past.
Yield Losses:
Regional Differences: None
Cultural Control Practices: Worse in younger trees
Biological Control Practices: NA
Post-Harvest Control Practices: NA
Other Issues: Damage may be severe to non-bearing trees; damage may have effects on early establishment.

Chemical Controls for Potato Leafhopper:

Leafhopper, White Apple and Rose
Type of Pest: Insect
Frequency of Occurrence: Annually
Damage Caused: WALH nymphs and adults are mesophyl feeders. Feeding injury causes a white mottling of the leaves and with heavy infestations the leaves can become nearly completely white. Feeding WALH also excrete a honeydew which may drop onto lower leaves and fruit. Once dried on the fruit, the honeydew appears as shiny, colored spots or streaks that are colonized by fungi and turn black and are difficult to remove. Under humid conditions, the honeydew remains moist and is an excellent media for sooty molds.
% Acres Affected: <20% 
Timing of Control: Petal fall – August.
Yield Losses: <10%. Effects on fruit size difficult to measure. Fecal spotting of fruit could decrease packout by 50-100%.><10%. Effects on fruit size difficult to measure. Fecal spotting of fruit could significantly decrease useful yield.
Regional Differences: None
Cultural Control Practices: Damage may be lessened by elimination of multiflora rose, the overwintering host of rose leafhopper.
Biological Control Practices: Several parasites, predators, and a fungus attack the WALH. Normally, natural enemies cannot adequately control the WALH in commercial orchards and growers must rely on insecticidal control.
Post-Harvest Control Practices: None
Other Issues: The WALH has developed resistance to the organophosphate insecticides in many apple growing regions.

Chemical Controls for White Apple Leafhopper:

Leafminer, Apple Blotch and Spotted Tentiform
Type of Pest: Insect
Frequency of Occurrence: Annually
Damage Caused: Leafminer injury, due to feeding within the mines, reduces the photosynthetic capability of the leaves and disrupts the growth regulating and ripening processes governed by hormones produced in the leaves. Severe leafminer infestations may cause leaf drop, premature ripening and fruit drop.
% Acres Affected: potential 100%
Timing of Control: Red visual traps can be used to determine thresholds; foliage also can be examined to determine level of infestation compared to thresholds. 1st--pink/petal fall; 2nd--early July.
Yield Losses: indirect pest; stresses tree's productivity
Regional Differences: None
Cultural Control Practices: None
Biological Control Practices: Several parasite and predator species suppress leafminer populations. Selecting insecticides which are least toxic to these natural enemies will enhance biological control.
Post-Harvest Control Practices: Flail mowing of leaf litter in autumn reduces overwintering leaf miner populations.
Other Issues: Insecticides are not effective against larvae once they have progressed to the tissue-feeding stage.

Chemical Controls for Apple Blotch and Spotted Tentiform Leafminer: