Prepared: May, 2003
State Rank: Second
Percent U.S. Production:15%
Acres: 8,500
Cash Value: 41,246,000 $US
Yearly Production Costs:3,343 $US per acre
Ninety percent of Texas's cabbage goes to fresh market and 10% is processed.
Production Regions
Approximately one half of Texas's commercial cabbage is grown in the Lower Valley, one third in the South Texas Winter Garden area and the remainder on the High Plains and Trans-Pecos.
Cabbage produces best in a fertile, well-drained, medium textured soil that has a pH ranging from 6.0 - 7.5. Planted when soil temperatures are between 50 and 100 F., coated or uncoated seed are bedded with an in-row plant spacing of 6 to 12 inches for fresh market and 9 - 15 inches for processing. Optimal growing temperatures are cool days (60 - 70o F) with cold nights (40 - 50o F) with 20-30 inches of water distributed uniformly throughout the growing season. General fertilization requirements are 150 pounds of nitrogen, 75 pounds of phosphorus, and 80 pounds of potassium per acre, generally applied in split applications.
The optimum time to harvest cabbage for fresh market is when 50 - 60% of the heads are solid, 6 - 8 inches in diameter, and weigh 3 or more pounds. Processed cabbage is harvested when 50 - 60% of the heads are solid, greater than 6 - 8 inches in diameter; and weigh 4 or more pounds. Direct-seeded cabbage is harvested 110 - 130 days after planting and transplants are harvested 60 - 80 days after planting.
The types of cabbages typically produced in Texas are red, green and Chinese. Commercial varieties currently include: Blue Vantage, Bravo, Cheers, Genesis, Grand Prize, Pennant, Rio Verde, Market Prize, Solid Blue 720, Vantage Point, and Fortuna.
Worker Related ActivitiesPlanting cabbage in Texas takes place from September through January in the Lower Valley and July through January in the Winter Garden. One month before planting the previous crop is shredded then fields are plowed, disced, floated and bedded. Just prior to planting, phosphate fertilizer and herbicides are applied. Plant and follow with irrigation applying nitrogen fertilizer through the irrigation system. The month following planting, cultivate, irrigate, and apply insecticides and fungicides as needed. The second month following planting, irrigate, cultivate and apply insecticides and fungicides as needed. The third month following planting - irrigate(generally twice) and apply insecticides and fungicides as needed. Harvest, pack and market, pack the fourth month after planting. The cabbage is hand-harvested and loaded bulk into wagons with some being field-packed into 50-lb mesh bags. Harvesting is from November through May in the Winter Garden and December through May in the Lower Valley.
Frequency of Occurrence:
Cabbage loopers, diamondback moths, and flea beetles are present annually, although severity of infestations vary from year to year. In South Texas, all stages of beet armyworm and fall armyworm may be found throughout the year.
Damage Caused:
Cabbage loopers are voracious feeders which can strip seedling foliage and in a short time cause stand loss. They feed on wrapper leaves and will burrow into the base of the cabbage heads, contaminating with body parts and a yellow green excrement. Often, when populations become crowded, a virus disease strikes, causing high larval mortality. Diamondback moth larvae feed on the underside of outer leaves, eating out a small area but leaving the thin epidermis intact causing a skeletonized appearance. Both loopers and diamondback moths will feed within heads, which provides protection from contact insecticides. They also damage the growing points and crowns of young plants, stunting growth and contaminating heads. Flea beetles eat numerous, very small, rounded or irregular holes in leaves and heavily damaged leaves may wilt, often killing or stunting the plant. Damage caused by the imported cabbage worm is similar to, and easily confused with, damage caused by the cabbage looper. They eat plant foliage rapidly and can strip infested plants in a short time. Larvae bore into heads contaminating them with body parts and a greenish brown excrement. The fall armyworm larva begins feeding on its egg shell immediately after hatching then will move to plant tissue near the soil surface. Larvae grow rapidly and can frequently do considerable damage. They will move in groups to other fields after devouring plants in the hatching area. Beet armyworm larvae may defoliate plants
Percent Acres Affected:Cabbage loopers and flea beetles affect 100% of the State's cabbage acreage. Diamondback moths, and beet armyworms affect 80%, fall armyworms 30%, and imported cabbage worms 10%.
Pest Life Cycles:
There are continuous generations of cabbage loopers in the Lower Valley with reproduction slowing down during cold periods. In colder areas, the insect overwinters as pupae in flimsy silken cocoons attached to plant residues. A complete generation occurs in 4 to 6 weeks in warm weather. Diamondback moth adults lay minute, yellowish-white eggs, 1 to 3 at a time. In 3-4 days the eggs hatch and the larvae generally feed on the underside of leaves. These larvae become full grown in 10 to 30 days. The pupa is usually fastened to the leaf's underside. The small moth emerges in 7 to 14 days and starts another generation. There may be two or three generations per year. Flea beetle adults overwinter in the soil, or in crop and weed residue. They become active in spring, feeding on host plants as new growth appears. Eggs are laid on or in soil near the plant base. Hatch is in about a week and larvae feed on plant roots or tubers for 2 to 3 weeks, followed by pupation and adult emergence. Life cycle from egg to adult may be completed in 6 weeks or less and adult feeding may extend over 2 months. One to four generations develop each year depending on species. In colder areas, the insect overwinters in the adult stage. Imported cabbage worms overwinter as pupae attached to food plant residue. A complete generation occurs in 4 to 6 weeks in warm weather. Fall armyworm moths lay eggs at night in clusters of 50 to several hundred, most often on blades of grass. Eggs hatch in 2 to 4 days and larvae become full grown in 2 to 3 weeks. Then they burrow 1 to 2 inches into the soil and pupate, remaining for 8 to 10 days before emerging as adults. Fall armyworm outbreaks usually follow wet seasons, especially during the summer and early fall. There may be five to ten generations annually. Beet armyworm eggs are deposited in irregular masses of about 80 eggs, covered with scales or hairs from the adult's body. Hatch is in 2 to 5 days and the larvae will feed for about 3 weeks before pupating in the soil. Egg-to-adult is 24 to 36 days and there may be four generations per cabbage season.
Timing of Control:
Infestations of these insects can occur throughout the growing season and insecticides should be applied as necessary based on field monitoring.
Yield Losses:
When present and not controlled entire fields can be lost to any of these chewing insects.
Regional Differences:
Cabbage loopers are a problem throughout the state. Diamondback moths are a severe problem in the High Plains and the Winter Garden and a significant problem in the Lower Valley. Flea beetles are a severe problem in the High Plains and the Winter Garden and a small problem in the Lower Valley. Imported cabbage worms are a problem in the High Plains, but not a problem in the Winter Garden nor the Lower Valley. Fall armyworms are a problem in the Winter Garden. Beet armyworms are a problem in the Lower Valley.
Cultural Control Practices:
Some cabbage varieties are more susceptible than others to cabbage loopers. Adverse weather conditions (cool and wet) will reduce cabbage looper and diamondback moth populations. No resistant variety to diamondback moths is available, but there are differences in susceptibilities among commercial varieties. Spunbound row covers can control flea beetles on seedlings where practical (e.g. smaller plantings and seed beds). However, yields of late plantings may be reduced by row covers.
Biological Control Practices:
Natural enemies may help to control cabbage looper and diamondback moth populations. At times, tachinid flies will parasitize up to about 60% of cabbage loopers in the Winter Garden. These natural enemies can be conserved by using insecticides that are less harmful to them. Mycotrol, a commercial product containing the entomopathogenic fungus Beauvaria bassiana, is still being tested against cabbage loopers and has shown some efficacy against diamondback moths but is not as effective as the spinosad materials. The spined soldier bug preys on the larvae of cabbage loopers, diamondback moths, flea beetles, fall armyworms, and beet armyworms and is available commercially. The pink spotted lady beetle (Coleomegilla maculata) attacks and kills imported cabbageworms. Pink spotted lady beetles can be present naturally and are available commercially. Parasites are also available however, along with commercial predators, are often not cost affective. Bacillus Thuringiensis (bt) products are used extensively, particularly prior to wrapping.
Resistance management:
Resistance management is a key aspect of diamondback moth control, because it is known to quickly develop tolerance to insecticides, such as the Bts and pyrethroids. Depending on the source of adults, insects found in a field may be resistant to pyrethroids, organophosphates, carbamates, and/or Bt products. Preliminary research suggests that there may be a possibility of cross-resistances to pyrethroids and spinosad. For these reasons it is essential to have a broad range of insecticides from different classes available for resistance management. For example, some growers are successfully managing diamondback moths by using alternating applications of Bts, pyrethroids, and spinosad early in the season, and then switching to organophosphate insecticides later in the season. It is estimated that without the availability of organophosphates, and without the registration of new materials having different modes of action, insecticide use could increase in cabbage largely due to diamondback moth infestations.
Efficacy Issues:
Spintor has proved to be very affective against diamondback caterpillars, although it is an expensive option, and some producers have reported control failures. Use of spinosad is expected to increase in the future as producers gain experience with the insecticide and as availability increases. Some materials (e.g. permethrin) perform better under cool weather conditions, while others (e.g. Bts) are most effective when weather is warm.
Chemical Controls: Also see tables on page 9 and 12.
| Pesticide | % A Trt. | Type of Appl. | Typical Rates | Timing | # of Appl. |
| acephate (Orthene 90S) |
10 | foliar | 3 fl oz | Apply when insects or eggs first appear and repeat as needed. | 1 |
| Target insects | cabbage aphids, cabbage looper, diamondback moth, and imported cabbage worm. | ||||
| endosulfan (Thiodan) |
100 | foliar | 1 qt 3EC | Apply when insects appear or feeding is noticed. Repeat as necessary but not more than 4 applications per season. | 3.5 |
| Target insects | diamondback moth, flea beetle, fall armyworm, harlequin bug, imported cabbage worm, cutworms, sweet potato whiteflies, and cabbage aphids. | ||||
| esfenvalerate
(Asana XL) |
100 | foliar | 6 fl oz | Apply when insects appear or feeding is noticed. Repeat as necessary but not more than 0.4 lb. ai/acre per season. | 1.5 |
| Target insects | cabbage looper, flea beetle, beet armyworm, imported cabbage worm, and cutworms. | ||||
| methomyl
(Lannate LV) |
45 | foliar | 1.7 pt. | Apply when insects first appear and repeat at 5 to 7 day intervals or as needed. | 1.8 |
| Target insects | cabbage looper, diamondback moth, fall armyworm, imported cabbage worm, and cutworms. | ||||
| permethrin
(Ambush 2EC) |
100 | foliar | 8.5 fl oz | Apply when insects or their damage first appears and repeat as needed. | 5 |
| Target insects | cabbage looper, diamondback moth, flea beetle, beet armyworm, imported cabbage worm, cutworms, and cabbage aphids. | ||||
| thiodicarb (Larvin) |
40 | foliar | 1 qt | Apply when insects or their damage first appears and repeat as needed. | 1.75 |
| Target insects | cabbage looper, diamondback moth, beet armyworm, imported cabbage worm, and cutworms. | ||||
Alternatives:
Several new insecticides currently under development, including Emamectin benzoate (Proclaim; Novartis), indoxacarb (Avaunt; DuPont), bifenthrin (trade name Capture), a pyrethroid, and chlorfenapyr (Alert) (from American Cyanamid), may become effective options for control of diamondback moth. Thiomethoxam, a new insecticide from Novartis (trade name Adage) may be a useful alternative for flea beetle control. Spinosad, trade name Success (from Dow AgroSciences) was recently labeled for several vegetables including cabbage. It can be used to control diamondback moth, imported cabbage worm, cabbage looper, armyworms- including beet armyworm, leafminers and thrips.
Frequency of Occurrence:
These soil insects are present annually with varying degrees of infestation.
Damage Caused:
As many as 100 species of white grubs may cause damage to vegetables. Grubs will feed on roots and other underground plant parts of many vegetable crops. Most severe infestations occur on crops following grass.
Fire ants form tall, hardened mounds in clay soils, which can damage equipment and slow down operations. They plug up and damage drip irrigation systems and can cause equipment failures by getting into electrical units. Ants will feed on seeds and seedlings and can cause stand failure. Ant stings can cause problems for field workers.
Root aphids feed on roots interfering with water and nutrient uptake resulting in plant stunting and poor cabbage development. The heads turn a purplish/reddish color making them unmarketable.
Cutworms can cause stand loss if present in sufficient numbers.
Percent Acres Affected:
Root aphids affect about 25% of the State's cabbage acreage, white grubs 5%, cutworms 5%, and fire ants 60%.
Pest Life Cycles:
White grubs can live from 1 to 3 years depending on the species. Adults emerge in the spring. Females lay eggs in the soil and after hatch the larvae migrate up and down their feeding zone with seasonal changes in temperature.
The fire ant is a social insect that lives in organized colonies inside mounds of dirt that may be more than 18 inches high. Periodically, winged reproductives take mating flights, often drifting for many miles. From egg to adult takes about 30 days which is followed by four larval stages and a pupal stage. There are both single queen (monogyne) and multiple queen (polygyne) colonies. The single queen form may build 40 to 80 mounds per acre, while the multiple queen form can have 200 to 800 mounds per acre.
Poplar petiole gall aphid, commonly known as the cabbage root aphid, is holocyclic, having a complete life cycle, alternating parthenogenetic with sexual reproduction. In south Texas, it starts a new cycle in the spring by mating on its primary hosts (Populus spp., such as cotton wood). As feeding occurs the aphids form galls on leaf petioles and after living in the galls for a number of generations, winged females migrate to their secondary cruciferous hosts (such as cabbage). Once colonized on roots, the aphids can reproduce parthenogenetically for many generations. In the spring, the winged adults fly back to the primary hosts, mate and lay eggs, starting another life cycle. Black cutworms deposit eggs singly or in small batches on lower leaves or stems and produce four or more generations a year. They overwinter as larvae or pupae. Variegated cutworms deposit eggs in batches on lower stems and leaves, may produce three or four generations in a year and overwinter as pupae. The larvae are often found on the soil surface, beneath leaves and other debris. Granulate cutworms are subterranean in habit, complete up to four generations per year and overwinter as larvae.
Timing of Control:
Insecticide applications are made at planting. Insecticides are applied to control fire ants throughout the season as mounds are observed.
Yield Losses:
Estimated yield loss if present and not controlled: root aphid 50%, white grub 20%, fire ants 15%, and cutworms 5%.
Regional Differences:
White grubs are a significant problem in the Winter Garden and a minimal problem in the Lower Valley and the High Plains. Root aphids are a moderate to severe problem in the Winter Garden and the Lower Valley and a minimal problem in the High Plains. Fire ants are a severe problem in the Winter Garden.
Cultural Control Practices:
Plants grown in light, sandy soils are more susceptible to injury from soil insects. Planting later, cleaning fields of weeds and plant residues, and keeping fields free from weeds when between crops helps prevent large soil insect populations.
Biological Control Practices:
Root aphids are attacked by lady beetles and dipterous fly predators.
Post-Harvest Control Practices:
Crop debris should be destroyed as soon as possible after harvest to minimize the spread of soil insect pests.
Chemical Control: Also see tables on page 6 and 12.
| Pesticide | % A Trt. | Type of Appl. | Typical Rates | Timing | # of Appl. |
| diazinon
(Diazinon AG500) |
60 | foliar, pre-plant, or side dress | 1.7 pt | diamondback moth and foliar aphids 1; root maggot 2. | 1.2 |
| Target insects | root aphids, white grub, cutworms, diamondback moth, flea beetle, and foliar aphids. | ||||
| chlorpyrifos (Lorsban 4E) |
25 | foliar or pre-plant incorporated | 1 qt. | Apply when insects appear and repeat at 7 to 14 day intervals. | 1 |
| Target insects | imported cabbage worm, cutworms, white grubs, diamondback moth, beet armyworm, flea beetles, root aphids, and cabbage aphids. | ||||
| carbaryl (Sevin ) |
5 | foliar
(fire ants - treat mounds) |
1.5 qt 4F; 20-40 lb 5 Bait; fire ants 3 Tbsps./2 gals./mound | Apply when insects or their damage appear and repeat at 7 - 14 day intervals as necessary, (for fire ants treat mounds as they appear). | 2 |
| Target insects | imported cabbage worm, cutworms, diamondback moth, flea beetle, harlequin bug and fire ants. | ||||
| rotenone (True Stop) |
1 | Apply to ant mounds | 2/3 cup/gal; 8 to 10 fl. oz./ 4-inch diameter mound | Apply when mounds are observed. | |
| Target insects | fire ants. | ||||
1 Apply when insects appear or when damage observed. 2 pre-plant incorporate.
Frequency of Occurrence:
Infestations of cabbage aphids and turnip aphids, etc. (foliage aphids) and whiteflies occur annually. Spider mites will generally occur about every 2 years. Harlequin bugs are a spring time Winter Garden cabbage pest and a High Plains spring or fall cabbage pest practically every year.
Damage Caused:
Harlequin bugs congregate in large numbers on plants, sucking juices until the hosts wilt and die. Large populations can appear rapidly and destroy a crop within two to three days. Cabbage aphids suck plant sap, and cause stunting; they can vector virus and will leave undesirable honeydew deposits. They give birth to living young and build up very rapidly. The presence of aphids can make cabbage difficult to market. Sweet potato whiteflies, both nymphs and adults feed by sucking plant juices. Heavy feeding gives plants a mottled appearance or causes them to turn yellow and die. The sticky honeydew excreted by the insects often glazes the lower leaves and permits the development of black sooty mold, thus detracting from appearance. Spider mites pierce leaf tissues and suck sap in larval, nymphal and adult stages. Plants attacked begin to lose color, fading from green to yellow and eventually turning reddish.
Percent Acres Affected:
Whiteflies affect 85% of the state cabbage acreage, harlequin bugs 25%, aphids 80%, and mites, 1%.
Pest Life Cycles:
Harlequin bugs feed and mate throughout the winter in warmer areas and adults hibernate in crop residues and other debris in colder areas. Eggs are laid on end in double rows on leaf undersides and look like small white kegs with two black hoops. Hatching occurs in 4 to 30 days and nymphs feed for 1 to 4 weeks before becoming adults. Three or more generations may occur yearly. Cabbage aphids overwinter as eggs on crop residue or host plants. Winged forms, less frequently found than wingless forms, enable the insect to move into a field from other areas. Females can reproduce without mating with males. Cabbage aphids are generally most abundant from January through March or April in the Lower Valley. Their severity is greatly influenced by weather patterns. Spider mite adults lay eggs on a leaf's underside and spin webs where eggs hatch and mites feed. Spider mites reproduce rapidly during hot, dry weather. Overlapping generations of sweet potato whiteflies occur in the Lower Valley during spring, summer and fall. Adults deposit elongated, yellow eggs and attach them to host by a short stalk. The Nymphal period is one month under cold conditions but one week when it's hot.
Timing of Control:
Infestations of sucking insects can occur throughout the growing season and insecticides should be applied as necessary based on field monitoring. Insecticide applications for cabbage aphid control may be made at planting. If harlequin bugs are observed, controls needs to be applied promptly.
Yield Losses:
Estimated yield loss from harlequin bugs, cabbage aphids, spider mites, and sweet potato whiteflies if present and not controlled is 60%, 45%, 35%, and 55%, respectively.
Regional Differences:
Cabbage aphids are a severe problem in the Winter Garden, a significant problem in the Lower Valley and a smaller problem on the High Plains. Sweet potato whiteflies are a severe problem in the Lower Valley and the fall Winter Garden crop but are not a problem in the High Plains. Spider mites are a significant problem in the Lower Valley and the Winter Garden. Harlequin bugs are a problem in the Winter Garden and the High Plains.
Cultural Control Practices:
Planting later, cleaning fields of weeds and plant residues, and keeping fields free from weeds when between crops help prevent large populations of sucking insects, particularly sweet potato whiteflies.
Biological Control Practices:
Naturally occurring predators, parasitoids, and pathogens help suppress cabbage aphid, sweet potato whitefly and spider mite populations. Increases in these pest populations are sometimes associated with applications of insecticides that have killed natural enemies. The pink spotted lady beetle attacks and kills cabbage aphids and spider mites. It can occur naturally and is available commercially. The convergent Lady Beetle (Hippodamia convergens) occurs naturally and is sold by insectaries for cabbage aphid control. If cabbage aphids are scarce, beetles and larvae may feed on small insect larvae, insect eggs, and spider mites. The common Green Lacewing (Neuroptera: Chrysopidae) is a predator of cabbage aphids, spider mites, and sweet potato whiteflies. They occur naturally and are available commercially.
Post-Harvest Control Practices:
Destroying crop debris as soon as possible after harvest is important to reduce sweet potato whitefly and cabbage aphid habitat.
Chemical Controls:
| Pesticide | % A Trt. | Type of Appl. | Typical Rates | Timing | # of Appl. |
| dimethoate (Dimethoate 4EC) |
30 | foliar | 1 pt. | When a damaging population of insects is observed. | 1.3 |
| Target insects | cabbage aphids, and flea beetles. | ||||
| methyl-parathion (Methyl-parathion) |
60 | foliar | 1 pt. | Apply when insects or their damage first appears and repeat as needed. | 1.5 |
| Target insects | harlequin bug, spider mites, cabbage aphids, cabbage looper, flea beetle, beet armyworm, and imported cabbage worm. | ||||
| lambda-cyhalothrin (Karate 1E) |
80 | foliar | 3.84 fl oz | Apply as required by scouting. Do not apply more than 1.92 pt per acre per season. | 4 |
| Target insects | harlequin bug, spider mites, cabbage aphids, sweet potato whiteflies (suppression), cabbage looper, diamondback moth, flea beetles, imported cabbage worm, beet armyworm, and cutworms. | ||||
| disulfoton (DiSyston) |
50 | side dress | 1 pt 8E | At planting. | 1 |
| Target insects | flea beetle and root aphids. | ||||
| imidacloprid (Admire, Provado) |
10 | soil | 11 fl. oz. 2F | At planting. | 1 |
| Target insects | cabbage aphids, root aphids, and sweet potato whiteflies. | ||||
Alternatives:
New materials include, pymetrozine (trade name Fulfill) and thiomethoxam (trade name Adage), may be effective alternatives for cabbage aphid and sweet potato whitefly control. Triazamate (trade name Aphistar) is new for control of aphids in cole crops, and leafy greens.
Frequency of Occurrence:
Broadleaf weeds present a constant problem in cabbage and control methods need to be applied annually.
Damage Caused:
Weeds reduce yields by competing with cabbage for space, sun, water, and nutrients. Unwanted plants can interfere with harvest and act as alternate hosts for diseases, nematodes, and insects.
Percent Acres Affected:
All cabbage acres are affected to some degree by broadleaf weeds.
Pest Life Cycles:
The broadleaf weeds: pigweed, purslane, false ragweed, and sunflower are native to Texas and are warm season annuals. Lambs quarter and kochia are introduced annual warm season broadleaf weeds. London rocket, mustard and henbit are introduced annual cool season broadleaf weeds. Ground cherry is a native perennial warm season weed.
Timing of Control:
Most herbicide applications are made pre-emergence to the weed, some are post-emergence.
Yield Losses:
Estimated yield loss if the weed is present and not controlled are: London rocket(20%), lambs quarters(50%), mustard(70%), pigweed(75%), purslane(45%), false ragweed(30%), sunflower(60%), ground cherry(60%), henbit(63%), and kochia(80%).
Regional Differences:
London rocket is a significant problem in the Lower Valley. Lambs quarters is a severe problem in the Lower Valley. Mustard is a severe problem in the Winter Garden and the Lower Valley. Pigweed is a severe problem in the High Plains, the Winter Garden and the Lower Valley. Purslane is a severe problem in the Winter Garden and the Lower Valley. False ragweed is a severe problem in the Winter Garden. Sunflower is a severe problem in the Winter Garden and the Lower Valley. Ground cherry can be a problem in cabbage fields in the Lower Valley. Henbit is found in the Winter Garden and kochia is found on the High Plains.
Cultural Control Practices: Cultivate 1 to 2 times after planting.
Chemical Controls: See Grass weed chemical control table on page 22 also.
| Pesticide | % A Trt. | Type of Appl. | Typical Rates | Timing | # of Appl. |
| trifluralin
(Treflan 4EC) |
60 | soil | 1-1.5 pt. | Apply pre-plant and incorporate. | 1 |
| Target weeds | broadleaf weeds and grasses including: Johnson grass (seedling), Texas panicum, henbit, kochia (fireweed), lambs quarters, redroot pigweed, rough pigweed, spiny pigweed, and purslane. | ||||
| bensulide (Prefar 4E) |
50 | soil | 5 qt. | Applied pre-plant incorporated or pre-emergence. | 1 |
| Target weeds | broadleaf weeds and grasses including: lambsquarters, redroot pigweed, and purslane. | ||||
| paraquat (Gramoxone Extra ) |
10 | apply to weed foliage | 1.5-3 pt. | Apply pre-plant, pre-emergence. Apply when weeds and grasses are succulent and growth is from 1-6 inches high. | 1 |
| Target weeds | emerged annual broadleaf weeds and grasses. Suppresses perennials. | ||||
| glyphosate (Roundup 4WS) |
10 | apply to weed foliage | annuals 0.75-3 pt., perennials 1-10 pt. | Apply prior to emergence of direct seeded corp or prior to transplanting. | 1 |
| Target weeds | emerged annual and perennial broadleaf weeds and grasses including Johnson grass. | ||||
| napropomide (Devrinol 50-DF) |
80 | soil | 2-4 lb. | Apply pre-plant incorporated, pre-emergence. May be applied to direct seeded and transplanted crop or surface applied after planting. | 1 |
| Target weeds | broadleaf weeds and grasses including: Johnson grass (seedling), lambs quarters, redroot pigweed, and smooth pigweed. Can be used to suppress common ragweed. | ||||
Frequency of Occurrence:
Grasses and sedges present an annual problem in Texas cabbage.
Damage Caused:
Grasses reduce yields by competing with cabbage for space, sun, water, and nutrients. They also interfere with harvest and act as alternate hosts for diseases, nematodes, and insects.
Percent Acres Affected:
All cabbage acres are affected to some degree by grassy weeds.
Pest Life Cycles:
Johnson grass is a tall, coarse, perennial grass with stout (up to three-quarter inches in diameter) rhizomes that was introduced into the United States in the early 1800s. It spreads by the rhizomes and is capable of producing more than 75,000 seeds per plant. Texas panicum is a Texas native 'velvety haired' leaf summer annual grass that reproduces by seeds. It will grow erect or close to the ground. Nutsedge, or nutgrass, is a perennial warm season weed introduced to Texas. Yellow nutsedge has a yellowish green color and produces rhizomes that radiate out from the plant. It reproduces by seed, rhizomes and tubers(nuts). Purple nutsedge is usually a smaller plant than yellow nutsedge that produces purple seed heads and "tuber chains" on radiating rhizomes. The sedges have thicker leaves than true grasses that are arranged in sets of three. The plant's stems are solid and triangular shaped.
Timing of Control:
Most herbicide applications are made pre-emergence to the weed, some are post-emergence.
Yield Losses:
Estimated yield loss from Johnson grass, Texas panicum, and nutsedge if present and not controlled is 20%, 50%, and 20%, respectively.
Regional Differences:
Johnson grass is a severe problem in the Winter Garden. Texas panicum is a severe problem in the Winter Garden and the Lower Valley. Nutsedge is a significant problem in the Lower Valley.
Cultural Control Practices: Cultivate 1 to 2 times after planting.
Chemical Controls:
| Pesticide | % A Trt. | Type of Appl. | Typical Rates | Timing | # of Appl. |
| sethoxydim
(Poast ) |
20 | foliar | 0.5-1.5 pt. | Apply post-emergence. | 1 |
| Target weeds | Annual and perennial grasses including: Johnson grass and Texas panicum. | ||||
Note: No affective herbicides are available for nutsedge control.
Frequency of Occurrence:
Alternaria and downy mildew are annual problems in Texas cabbage. Both occur late in a crop cycle when the canopy is dense and spray coverage difficult. Powdery mildew occurs frequently in the Winter Garden on cabbage and related brassicas.
Damage Caused:
The first symptom of Alternaria leaf spot on cabbage is minute dark spots on seedling stems and leaves. These spots enlarge and are marked with concentric rings of light and dark brown, giving a bull's eye appearance. Severe infection will result in large dead areas at lesion sites. Alternaria in late plantings predisposes plants to bacterial soft rot. An early symptom of downy mildew can be seen on the underside of leaves as gray, fluffy, downy growth in well-defined spots. Leaves will later develop small black spots, along with general yellowing. Powdery mildew appears as a white, powdery growth on the upper surfaces of leaves and on the exposed head.
Percent Acres Affected:
An estimated 65% of the state cabbage acreage is affected by alternaria, 80% by downy mildew. About 25% of fields are affected with powdery mildew.
Pest Life Cycles:
The Alternaria fungus overwinters on cabbage residue, on seed, or on related brassicas. Spores are disseminated by wind or water. Downy mildew is promoted by cool wet weather in the spring and fall. Downy mildew overwinters in plant debris or on cruciferous weed hosts. It spreads in the field with splashing water during cool weather, and is primarily a problem during the fall. With powdery mildew conidia are produced in abundance in just days after initial infection, allowing for repeated secondary spread within a season. Airborne conidia from long distances may be the most important initial innoculum in a cabbage field.
Timing of Control:
Fungicide applications should be made periodically from cabbage seedling stage through harvest. Fungicides are generally applied to prevent Alternaria and downy mildew. Powdery mildew is much less of a problem. Applications should be after mid-season to protect the tight wrapper leaves on the developing head. It is recommended that growers begin fungicide applications with the less expensive broad spectrum fungicides such as mancozeb and then upgrade to chlorothalonil during wet weather or after Alternaria or downy mildew is found in the field or area. Upgrade to chlorothalonil + mefenoxam when downy mildew becomes a problem.
Yield Losses:
Estimated yield loss from Alternaria if present and not controlled is 50%, downy mildew 55%, and powdery mildew 5%.
Regional Differences:
Alternaria is a severe problem in the Lower Valley, a significant problem in the Winter Garden, and a minimal problem on the High Plains. Downy mildew is a severe problem in the Winter Garden and the Lower Valley and a minimal problem on the High Plains. Powdery mildew is a minimal problem in the Winter Garden and the Lower Valley.
Cultural Control Practices:
Hot water treatment will rid seed of the Alternaria organism. Downy mildew and powdery mildew control approaches include elimination of cruciferous weeds. Rotation away from crucifers for a minimum of three years can help in disease management. No resistant varieties are available.
Post-Harvest Control Practices:
Crop debris should be destroyed as soon as possible to reduce the local Alternaria and downy mildew sources of inoculum and to initiate decomposition.
Chemical Controls:
| Pesticide
|
% A Trt. | Type of Appl. | Typical Rates | Timing | # of Appl. |
| chlorothalonil (Bravo 720) |
85 | Foliar | 1.5 pt. | Apply after transplants are set in the field, shortly after emergence of field-seeded crop, or when conditions favor disease development and repeat at 7 to 10 day intervals as necessary. | 3 |
| Target diseases | alternaria and downy mildew. | ||||
| mancozeb/ maneb (Maneb 75DF, Manex FL) |
60 | Foliar | 2 lb. DF, 1.6 qt. FL | Apply at 7 to 10 day intervals. | 1 |
| Target diseases | alternaria and downy mildew. | ||||
| mefenoxam (Ridomil Gold/Bravo) |
30 | Foliar | 1.5 lb. of WP | Apply when conditions favor disease development but before infection and repeat at 14 day intervals. | 1.5 |
| Target diseases | downy mildew and Alternaria. | ||||
Alternatives:
| Alternative | Efficacy |
| For Alternaria control | Recent research has shown that azoxystrobin (Quadris), tebuconazole (Folicur), and iprodione (Rovral) are more effective than the currently labeled fungicide, chlorothalonil. Trifloxystrobin (Flint) may also provide good control. |
Frequency of Occurrence:
Damping off occurs annually in the Winter Garden where, because of high temperatures, it is a big problem in July and August plantings. It will occur every year in spring plantings in the High Plains if treated seeds are not used. It is not a problem in the Lower Valley.
Damage Caused:
Damping off causes stand loss by girdling and killing seedlings.
Percent Acres Affected:
About 15% of statewide cabbage acreage is affected by damping off.
Pest Life Cycle:
Damping-off is caused by fungi present in the soil, including species of Rhizoctonia and Pythium. Pythium spp. (Phycomycetes) mostly cause seed-rot or 'preemergence damping-off'. Rhizoctonia spp. (imperfect stage of the Basidiomycete, Thanatephorus cucumeris) is sometimes described as a 'postemergence damping-off'. Germinating seed and seedlings, especially weak ones, are vulnerable to attack by these fungi during periods of unfavorable growing conditions.
Timing of Control:
Use treated seed.
Yield Losses:
Estimated yield loss if damping off is present and not controlled could reach up to 75% under conditions of high soil temperature.
Regional Differences:
Damping off is a severe problem in Winter Garden early plantings (summer), a potential problem on the High Plains, but not a problem in the Lower Valley.
Cultural Control Practices:
The general methods employed to prevent damping-off consist of : 1) proper soil preparation and management to provide for good soil drainage, structure, aeration, water-holding capacity and plant nutrition, 2) the use of fungicide-treated seed with high germination, 3) proper seeding rates to avoid thick plant stands, poor air movement and low light intensity and 4) proper planting depth and soil temperature to assure rapid seedling emergence. Planting healthy transplants is helpful.
Biological Control Practices:
No resistant varieties are available to curb the occurrence of damping off. Trichoderma spp. (trade name BIO-AG 22G) is one registered soil control pesticide. Mycoparasites may be important
Chemical Controls:
| Pesticide | % A Trt. | Type of Appl. | Typical Rates | Timing | # of Appl. |
| thiram
(Thiram) |
45 | Seed treatment | 8 oz./cwt seed | Pre-plant. | 1 |
Frequency of Occurrence:
Nematodes and tip burn occur annually. Hollow heart occurs after a cold spell and soft rot occurs when there is a wet warm spring. Occurrences of southern blight (hot weather disease) and black leg are rare state-wide. Southern blight is seen in the Lower Valley about every other year. Black rot, and white mold occurrence is sporadic. Black rot may be seen in the High Plains about one out of every 4-5 years and about one out of every 6-7 years it is severe enough to merit treatment. White mold occurs in some Winter Garden cabbage fields about every 3-5 years.
Damage Caused:
Southern blight is caused by a soil-born fungus, Sclerotium rolfsii. A whitish fungal growth develops around the base of plants at the ground line. Small seed-like structures (sclerotia) are found with natural fungal growth. They are white at first and later turn dark brown to black. Plants wilt and die suddenly after the fungus girdles the stem. With black leg, small spots with ashen-gray centers and black dots develop on plant leaves and stems. These gradually enlarge extending to the roots. In advanced stages the root system develops a dry rot. Wilted leaves tend to remain attached to the stem instead of defoliating like plants infected with yellow or black rot. Soft rot causes the plant stems to decay and have a foul odor. Also, during storage and transit cabbage with soft rot develops a slimy decay with a foul odor. Symptoms of nematode damage consist of wilting during periods of moisture stress, stunted plants, chlorotic or pale green leaves, and reduced yields. Most characteristic symptoms, however, are those occurring on underground plant parts. Infected roots are retarded in growth and lack fine feeder roots. Rotting of roots may develop late in the season. The fungus that causes white mold initially infects at the soil line or at the petiole base on the lower stalk. The whole head is rapidly invaded and converted into a watery shriveled mass with white mycelium. Because it is a stress problem tip burn damage varies widely among fields and between seasons. It is more common at certain times of the year, and more prominent on certain varieties. Hollow heart can cause blemishes on the cabbage making it unmarketable. Black rot infection usually begins near margins of leaves. Yellow areas develop along the margins, progressing into the leaf in an inverted-V shape, then into the head. Veins in the affected areas are black and a black discoloration is observed in the stem when split lengthwise. Black rot is favored by warm wet conditions.
Percent Acres Affected:
An estimated 10% of the state-wide cabbage acreage is affected by hollow heart and tip burn and 5% by nematodes. Bacterial soft rot affects about 35% of the acreage and black leg 3%. In a 5-year period, 15% of cabbage fields will be affected with black rot.
Pest Life Cycles:
The fungus that causes black leg is carried on and within seed and can persist on infected plant residue for one or two years. Spread is dependent on dew, rain and irrigation water. The bacteria that causes soft rot is spread by insects, tools, rain, irrigation, clothing, and affected plant tissue. It usually develops in water saturated fields. Soft rot begins in areas on the cabbage that have been bruised, particularly during periods of high temperature and high humidity. Southern blight is caused by a soil-borne fungus which overwinters as sclerotia and in host debris in the soil. A characteristic of the fungus is that it is generally most active in the upper 2 or 3 inches of soil but will survive at greater depths. The fungus is more active in warm, wet weather, and is favored by the presence of undecomposed crop residue.
Second stage root knot nematode larvae penetrate the plant at or near the root tip and become sedentary. The nematode then begins to release an enzyme which causes plant cells surrounding the head region to enlarge, forming giant cells that provide nourishment for the parasite. During this time female nematodes swell until they become pear-shaped or oval. Egg laying begins around 20 days after penetration of the host and continues at a rate of approximately 30 per day for two weeks. The average life cycle is about 25 days. Populations build up rapidly under favorable environmental conditions.
The white mold fungus spends the summer in the soil as sclerotia (asexual long-term survival structures) and in host plant debris. During cool wet weather, sclerotia germinate directly or produce sexual fruiting bodies that release airborne spores capable of infecting cabbage and other cultivated crucifers, certain other vegetables, herbs, ornamentals, alfalfa, and several common winter weeds (bur clover, London rocket, wild mustard, sow thistle, and others). Weedy fallow can allow the fungus to maintain a population density capable of causing problems in cabbage.
Hollow heart develops when there is a boron deficiency in the soil. Tip burn is caused by plant stress and is more prominent on certain varieties. The bacterium that causes black rot may attack cruciferous plants at all stages of growth. It is seed-borne and does not survive for more than 12 months in the soil and debris of irrigated fields. Some wild plants may act as hosts harboring the bacterium while crucifers are absent from commercial fields. Young plants resulting from infected seed serve as a source of secondary infection. Under the crowded conditions in a transplant greenhouse, in the field and during periods of rain, the bacteria can spread quickly to nearby healthy plants. Black rot is more likely to develop in a wet warm season, under overhead irrigation, and in poorly drained fields.
Timing of Control:
Seed treatment is recommended for black leg and black rot. Soil applications before planting can be made for nematode control. Foliar applications can be made to minimize loss from black rot as soon as infection is detected.
Yield Losses:
Estimated yield loss, if present and not controlled, is 5% with hollow heart, nematodes, tip burn, and southern blight. It is 1% with soft rot and black leg. Potential loss from black rot is 100% if seed is not tested and fields are not treated when necessary. Estimated yield loss from white mold is 20% without prudent crop rotation and careful site selection.
Regional Differences:
Black rot and tip burn are all found to some degree in all three major cabbage growing areas in the state. The Lower Valley and the Winter Garden both have some occurrence of nematodes, southern blight, and white mold. Hollow heart is present at times in Lower Valley and High Plains cabbage fields. Black leg is sometimes a problem in the Winter Garden and the High Plains.
Cultural Control Practices:
Growers employ the following cultural control practices: adapted varieties, clean seed, planting late in cooler weather, rotations(following corn, small grains, etc.), seed bed preparations to minimize crop debris near the bed surface, and careful and frequent irrigation to manage soil temperature and moisture. Specific black leg control practices include avoiding soils where cabbage or related plants were grown within the last four years. Destroy crop residues by shredding and deep burial. The best means to control soft rot includes avoiding late planting, proper handling of the cabbage during harvesting, packaging and storing along with keeping temperatures low. Also a long rotation and planting on raised beds in well drained soil are recommended to prevent field infections. Nematode control includes crop rotation (three to four years with resistant crops such as cereal crops), resistant or tolerant varieties, dry summer fallow with cultivation every three to four weeks where possible and planting in nematode free fields. Black rot control is achieved by following a 2 year rotation, by planting disease-free seed, and seed that has been treated with hot water to eliminate seed-borne bacteria. Seed costs include extensive seed testing to identify problem lots. To prevent white mold growers can avoid planting cabbage in fields or parts of fields where they know the soil is infested or where the disease has recently occurred. It is helpful to rotate with warm season crops and white mold resistant cool season crops.
Biological Control Practices:
A fungal mycoparasite, Coniothyrium minitans shows promise for control of white mold in Europe. If nematodes are a problem growers can plant resistant varieties. Also, the biological pesticide Myrothecium verucaria (trade name DiTera ES) is registered for nematode control. Some new adopted varieties are resistant to hollow heart.
Chemical control:
Copper and/or mancozeb can be applied as foliar sprays when black rot is observed. No chemical treatment is available for control of hollow heart, white mold, tip burn, southern blight, and bacterial soft rot. Hollow heart is caused by boron deficiency and is not pathological. Boron can be applied to the soil but the application rate is quite sensitive (1 ppm is too low and 3 ppm is too toxic). Tip burn is not a pathological problem but stress and variety related. To minimize occurrence of bacterial soft rot growers should avoid late planting that will mature in hot weather. Several chemicals are registered for nematode control including: fenamiphos, ethoprop, metam-sodium, chloropicrin, methyl bromide + chloropicrin, dichloropropene + chloropicrin, and DiTera--a biological but generally none are applied because they are not cost effective.
Authors
Kent Hall and Rodney L. Holloway
State Contacts
Rodney HollowayNoel Troxclair
Extension Entomologist
Texas Cooperative Extension
Uvalde, Texas 78802
n-troxclair@tamu.edu
Frank Dainello
Extension Horticulturist
Texas A&M University
College Station, Texas 77843
f-dainello@tamu.edu
Dudley Smith, Professor
Department of Soil and Crop Sci.
Texas A&M University
College Station, Texas 77843
dt-smith@tamu.edu