Crop Profile for Leafy Greens in North Carolina Prepared: July, 2003 General Production Information ● North Carolina growers produced 243,000 cwt. of collards in 2001. North Carolina ranked third among the states in the production of collards in 2001, representing 14.5 percent of the U. S. production. A total of 2,800 acres of collards were planted and 2,700 acres of collards harvested in North Carolina in 2001. Growers in the state produced 90 cwt. of collards per acre in 2001, valued at $6,318,000. ● Growers in North Carolina produced 147,000 cwt. of turnip greens in 2001. North Carolina ranked third among the states in the production of turnip greens in 2001, representing 13.1 percent of the U. S. production. A total of 2,200 acres of turnip greens were planted and 2,100 acres of turnip greens harvested in North Carolina in 2001. Growers in the state produced 70 cwt. of turnip greens per acre in 2001, valued at $3,822,000. ● The production of mustard greens in North Carolina totaled 91,000 cwt. in 2001. North Carolina ranked fifth among the states in the production of mustard greens in 2001, representing 8.8 percent of the U. S. production. A total of 1,400 acres of mustard greens were planted and 1,300 acres of mustard greens harvested in North Carolina in 2001. Growers in the state produced 70 cwt. of turnip greens per acre in 2001, valued at $2,457,000. Production Regions Collards, kale, turnip greens and mustard greens are produced in all three of the regions of North Carolina, the Coastal Plain, Piedmont and Mountains. Leading counties in acreage and production of leafy greens include Sampson, Duplin, Cumberland, Pitt, Wilson, Lenoir, Greene, Wayne, Richmond, Johnston, Halifax, Edgecombe, Onslow, Robeson and Columbus. Figure 1. Leading leafy green-producing counties in North Carolina (shaded in green). The Crop Profile/PMSP database, including this document, is supported by USDA NIFA. Production Practices Collards, kale and other leafy greens (mustard and turnip) are cool season crops and are grown in the early spring and fall for maximum yields and quality. Kale can withstand temperatures in the upper teens; however, the other greens can withstand medium frosts. Planting dates for leafy greens in the state's Coastal Plain, Piedmont and Mountains are provide in Table 1. Leafy greens grow best in well-drained soils, rich in organic matter. Loams generally produce the greatest yields of leafy greens; however, sandy loams are better for overwintering and spring crops. A soil pH of 6.0 to 6.5 is optimum. Leafy greens require quick, continuous growth to achieve the best quality. Nitrogen is needed for good color and tenderness. Soil testing is recommended; however, for average soils growers use 600 pounds of 10-10-10 fertilizer per acre before planting and sidedress with 15 to 30 pounds of nitrogen per acre after seeding or transplanting. When planting leafy greens, collards can be transplanted or direct seeded, while mustard and turnips are direct seeded. Irrigation of leafy greens is important to provide adequate moisture for continuous growth of the crop. The entire plant or individual leaves can be harvested. At harvest, leafy greens are often packed in ice to maintain freshness for distance shipping. Table 1. Planting dates for leafy greens in North Carolina. Region Spring Fall Coastal Plain February 1 - April 15 August 1 - September 15 Piedmont February 15 - April 30 July 15 - September 15 Mountains March 1 - August 15 Varieties of collards planted by North Carolina growers include Morris Heading, Vates, Georgia Southern, Champion, Carolina and Blue Max, while kale varieties include Siberian, Winterbor, Blue Armor and Vates. Varieties of mustard greens planted by growers in the state include Southern Giant Curled and Tendergreen (Mustard Spinach), and turnip green varieties include Purple Top White Globe and Seven Top. Worker Activities For some plantings, workers mechanically transplant young seedlings of collards and kale. Crops of mustard and turnip are always direct seeded and fall crops of collards and kale can be direct seeded or transplanted. Workers on tractors will be in the field for the one to three cultivations necessary for weed control for all the leafy green crops. Sometimes cultivation is not sufficient for weed control. It is necessary to hoe collards and kale plantings and for this activity workers may be in the field for a day. During a spray application, one worker will be in the field driving a tractor with the sprayer. During the one to six harvests, workers are in the field for harvest-related work. Table 2 lists the times that workers may be in the field for each of the leafy green crops. Table 2. Activities for which workers are in collard, kale, mustard green and turnip green fields. Collards Kale Mustard Turnip Activity: Plant Seed Plant Seed Seed Seed Crop establishment M/H 1 M M/H M M M Pesticide application M M M M M M Cultivation for weeds M M M M M M Hoeing H H H H -- -- Harvesting 3-6H 3-6H 3-6H 3-6H /1M 3H/1M 3H /1M 1 M = machine; H = hand. Insect Pests Insect pests of leafy greens (i.e., collards, kale, mustard greens and turnip greens) in North Carolina include the cabbage worm complex (cabbage loopers, diamondback moths, imported cabbageworms, corn earworms, beet armyworms, cutworms, and cabbage webworms), Harlequin bugs, stink bugs, aphids (cabbage and turnip), flea beetles, vegetable weevils, thrips, whiteflies, and root maggots. These insects must be managed throughout the production season, and especially in the summer and fall. Table 3 contains a list of insects for which North Carolina growers used insecticides to produce leafy greens in 1999. Approximately 78 percent of North Carolina growers used insecticides in 1999. Table 3. Insects for which insecticides were used by North Carolina growers in producing collards, kale, mustard greens and turnip greens during 1999, according to a mail survey of North Carolina leafy green growers conducted in April 2000. Percent of Leafy Green Growers Reporting Insect 1 Insect Collards Kale Mustard Greens Turnip Greens Aphids 44.90 16.33 26.53 28.57 Cabbage loopers 77.55 14.29 16.33 16.33 Imported cabbageworms 44.90 14.29 14.29 18.37 Diamondback moths 55.10 18.37 22.45 24.49 Flea beetles 20.41 14.29 18.37 18.37 Harlequin bugs 34.69 12.24 10.20 12.24 Root maggots 8.16 6.12 6.12 6.12 Stink bugs 24.49 10.20 14.29 14.29 Thrips 16.33 6.12 10.20 10.20 Vegetable weevils 14.29 10.20 10.20 12.24 Whiteflies 26.53 10.20 10.20 12.24 1 Of the 63 leafy green growers responding to the mail survey, 49 respondents used insecticides to control insects in 1999. Cabbage loopers, Trichoplusia ni (Hubner) Cabbage loopers feed on a variety of vegetable crops, including leafy greens. They are destructive pests that can cause economic damage to these crops. The adult is a brownish-gray moth with a figure-eight design in the forewing and migrates from overwintering sites in Florida and adjacent states into North Carolina in June in most years. Small round greenish-white eggs are deposited singly on the upper and lower sides of leaves and hatch in several days into larvae that are green with white stripes running the length of the body. There are three or more generations of cabbage loopers per year in North Carolina. Damage to crops occurs as a result of larval feeding on the undersides of the leaves. Management of cabbage loopers primarily involves insecticides. Promotion of natural enemies is also helpful in cabbage looper management. Adults are attracted to both black light and pheromone insect traps which can used for monitoring purposes. Diamondback moths, Plutella xylostella (Linnaeus) Diamondback moth larva are serious pests of collards and other leafy greens in North Carolina. The adults are gray moths that are about 1/3 inch in length. Male moths have three yellow diamond-shaped markings on their backs. Female moths lay small yellow to white eggs singly or in small groups on the leaves or stalk of their host plants, which hatch in 5 to 6 days. Larvae are light green in color, tapered at each end, and covered with tiny, erect black hairs. The larval stage of the diamondback moth consists of 4 instar stages lasting 10 to 30 days. There are 5 to 6 generations of diamondback moths per year in North Carolina. Damage to cropsj is caused by the larvae feeding on plant tissue on the undersides of the leaves, leaving holes in the leaves. Diamondback moth larvae can be managed through the use of insecticides; however, they have become increasingly difficult to control due to insecticide resistance. Promotion of natural enemies (i.e., parasites, diseases and predators) is also helpful in diamondback moth larvae management. Adult moths are attracted to sex pheromone traps (water pan traps) which can used for monitoring purposes. Mating disruption using Check Mate sprays are under evaluation. Figure 2. County Extension agent checking diamondback moth sex pheromone trap. Photograph by Kenneth A. Sorensen. Imported cabbageworms, Pieris rapae (Linnaeus) The adults are white moths with 3 or 4 black spots on their wings. Eggs are laid singly on leaves of the host plant. Larva are velvety green with a slender orange stripe down the middle of the back and along each side and 1-1/4 inches in length when fully grown. There are 3 or 4 generations of imported cabbageworms each year.