Commercial Production of Southern Peas

Southern peas also are known as cowpeas, field peas, protopeas, crowder peas, and black-eyed peas. Southern peas are susceptible to cold and are grown mostly in the southern states.

Southern peas are identified by color of hull, seed and embryo area, or by spacing (crowding) of seed within the pod. As examples, there are purplehulls, cream peas, pink- or black-eye peas, and crowder peas. Classifications often overlap (e.g., pinkeye purplehull).

Variety Selection

Many varieties of Southern peas are available. Choose one based on personal preference, pest resistance, yield, plant habit, and concentration of pod set. Some popular varieties are listed in Table 1.

Soils and Fertilizers

Southern peas grow on a variety of soils but grow best in soils with a pH between 5.5 and 6.5. Avoid planting peas in highly fertile soil. Excessive nitrogen levels stimulate vine growth and prolong the period to harvest.

Have your soil tested, and follow lime and fertilizer recommendations. Spread lime (as indicated by soil test) several months before planting.

Band fertilizer 3-4 inches deep and 2-3 inches away from the seeds or broadcast and disc in all fertilizer (including nitrogen) before planting. Peas have nitrogen-fixing bacteria and need only an initial application of 30 pounds of actual nitrogen. Inoculation of seed with cowpea bacteria can be beneficial.

Irrigation

Southern peas are among the more drought-tolerant vegetables, but irrigation under droughty conditions improves yields. The critical irrigation period is during blooming. For highest yields, peas should receive 1 inch of water each week, either by a rainfall or by irrigation.

Planting Dates

Surface soil should be 60 - 65 °F before planting. Seeds decay in cool, wet soils. Approximate early dates for areas in Mississippi include

Spacing and Seed Rate

Make certain row spacings are suitable for equipment if you plan to cultivate. Seed are often spaced 4-6 inches within the row, 30-42 inches between rows, and are planted to a depth of 1 inch.

Amount of seed to sow one acre depends on seed weight, germination percentage, and plant spacing. Recommended field-seeding rates are approximately 18 to 25 pounds per acre. Stands as low as 8-9 inches between plants are acceptable. Stands with 1-2 inches between plants in the row result in a dense tangle of vines.

Cultivation and Weed Control

Plan weed control before planting since control is important for good growth. Practice shallow cultivation to control weeds. Refer to Table 2 for information on herbicides to use on specific weed problems. Always follow manufacturers' instructions carefully when using their products.

Disease Control

Southern peas are susceptible to seedling disease caused by several fungi that may be present in the soil or carried on the seed. These fungi are Rhizoctonia solani, Pythium spp., and occasionally species of Fusarium. Symptoms of seedling disease vary and include seed rot and death of young seedlings before or shortly after emergence. Surviving infected plants generally have discolored roots, exhibit stunted growth, wilt when soil moisture is limited, and yield poorly. Control of seedling disease is difficult. Because no southern pea variety is resistant to the problem, the following measures help reduce losses from seedling disease:

• Use high-quality planting seed treated with Apron 25 W fungicide to help control seedling disease caused by Pythrium spp. Captan may also be applied to seeds to help control Rhizoctonia solani.
• At planting, incorporate Ridomil 2E for additional control of Pythium seedling disease. Refer to the product label for approved rates.
• Plant in warm, well-prepared soils, which promote faster seed germination and seedling development.

Southern blight is another disease that occasionally attacks stems and roots of southern peas. The first visible symptoms show up as a progressive yellowing and wilting of foilage. Infected plants die within a few days after foliage symptoms become apparent. A distinctive symptom of southern blight is the appearance of a mass of white cottony growth, which appears on the stem just above the soil line. Within this growth, numerous small, round, tan to dark-brown seed-like structures are formed. These structures (referred to as sclerotia) remain in the soil and cause disease in future seasons.

Control southern blight by burying crop debris and sclerotia to a depth of at least 6 inches as far ahead of planting as possible. Follow a 4- or 5-year rotation with other crops to help reduce incidence of southern blight. Rotation will also help control other soil-borne diseases that attack the crop. Additionally, avoid "dirting" plants during cultivation because this often throws infested soil against plant stems. MCES Plant Disease Dispatch M-602 provides additional information on the control of southern blight.

Virus Disease

Several viruses can attack Southern peas. The characteristic symptom of mosaic virus diseases is an intermixing of light- and dark-green areas. Mottled areas are irregular in outline and may follow the main veins. Infected leaves are frequently stunted, and often there is a slight puckering and curling of leaf edges. Infected plants are usually dwarfed and bunchy, and yields are reduced. Mosaic diseases also can result in malformed fruit or pea pods. Plants infected during seedling stages may be barren and fail to produce.

The best way to prevent large yield losses from virus diseases is to grow tolerant varieties. Control practices include

• Purchasing certified seed.
• Controlling weeds.
• Removing plants showing virus symptoms.

Plant Disease Dispatch M-615 has additional information on virus diseases of vegetables.

Fusarium Wilt

Lower leaves often turn yellow on one side of the plant. Infected plants are usually stunted and wilted as the organism develops in the food- and water-conducting tissues. Brick-red tissue can be observed in the stem when it is split lengthwise.

The best control of fusarium wilt is the use of resistant varieties. When resistant varieties are not used, it is important that root-knot nematode control practices be followed since nematodes increase the plant's susceptibility to fusarium wilt.

Root-Knot Nematodes

Roots infected with root-knot nematodes become knotted and galled. Above-ground symptoms appear as nutrient deficiencies, stunting and often wilting because the root systems are incapable of absorbing adequate amounts of water and nutrients. Do not confuse with symptoms of nodulating bacteria. Nodules are attached to sides of roots, and galls are within the roots.

Root-knot nematodes can be harmful to Southern peas in another way, because the injuries to the roots make the plants much more susceptible to attack by fusarium wilt. In addition to detecting the presence of nematodes by observing galled roots, you can detect nematodes by a soil test.

Soils can be tested (free) by sending a sample to the Extension Plant Pathology Department, Box 9625, Mississippi State, MS 39762, or by taking a sample to your county Extension office.

Once it is determined that nematodes are present, certain practices help reduce nematode populations. These practices include crop rotation, fallowing, sanitation, weed control, and planting resistant varieties. In Mississippi, varieties that resist nematodes also resist fusarium wilt and are tolerant of many viruses.

Pest Control

Insects can be a detriment to producing high-quality peas in Mississippi. Insects damage or reduce stands, lower quality, or decrease yields. In most cases, applications for the control of these pests can be made on an as-needed basis. However, in the case of some insects (e.g., cowpea curculio), applications usually are made as scheduled sprays.

Following are description and control information for some insects that may be found in pea fields.

Aphids

These are small, green soft-bodied insects that feed by piercing the plant tissue and withdrawing plant juices. Infestations of this pest develop on leaves and the fruiting stems. Their feeding, especially on the fruiting stem, reduces the amount of plant nutrients available for pod and pea development. Infested foliage turns yellow and dies. This insect also produces large quantities of a sugary material called honeydew that supports the growth of the fungus sooty mold. It is dark in color and reduces the amount of sunlight reaching the leaf. Aphid populations may occur anytime during the year; however, they are more likely to be found during mild, damp weather.

Thrips

Thrips are small (1.24 mm or less) insects that have two pairs of long narrow wings fringed with hairs. They are found on peas where they feed on either the blooms or on the foliage. Thrips feed on the underside of the leaves throughout the growing season, reaching maximum densities about a month after planting.

North Carolina reports 6 to 10 thrips per leaf cause some yellowing but relatively little economic damage. Damage by this insect is characterized by a yellow striping and a cupping of young leaves. It is often difficult to distinguish this damage from that caused by disease or other pests.

To check for thrips, shake the plants over a piece of white material--the straw-colored thrips stand out against the white background. Observations have to be made quickly, because adult thrips fly from the cloth.

Cowpea Curculio

This insect in Mississippi has the potential for being the most damaging pest of Southern peas. It is a small weevil that causes blister-like spots on the surface of the pod. These spots result from adults' puncturing the pod to feed or to lay eggs. Punctures from feeding result in small malformed peas, and the results of egg laying are numerous legless grubs that destroy developing peas. The insect, as an adult weevil, overwinters in ground trash, crop residue, or grass clumps. The insects begin emerging from overwintering sites between mid-March and mid-April.

Leaf-Feeding Beetles

Three beetles in Mississippi may feed on peas. These beetles are the Mexican bean beetle, bean leaf beetle, and the 12-spotted cucumber beetle. Their foliage-feeding habits cause irregular shaped holes in the leaves.

The immature and adult Mexican bean beetle can be found feeding on leaves. However, only the adults of the bean leaf beetle and spotted cucumber beetles feed on leaves. Watch for bean leaf beetle damage in pea fields located near soybeans.

Defoliation by these beetles should not be allowed to exceed 20 percent before bloom or 15 percent between bloom and pod fill. If treatments are needed, select one of the materials listed under corn earworm (Table 5).

Other Insects

In some years, the corn earworm, tarnished plant bug, or stink bugs may cause problems on peas. Feeding by the tarnished plant bug causes the plant to shed blooms and/or young pods. Stink bugs cause serious damage, especially on late-planted peas, by puncturing the pods and feeding on developing peas. The corn earworm chews holes in the pods, destroying young peas. Be alert for earworm problems around maturing corn or sorghum fields.

Check Table 3 for recommended materials for control of insects.

Harvesting

If you contract with a processor, he will specify the stage of maturity to harvest.

One rule is to harvest fresh-market peas about 16-17 days after bloom, depending on temperature. Purplehulls should be harvested for green peas when pods are 50 percent purple. Silverskins should be harvested for green peas when green pods begin to turn yellow. Mature pods are silver or tan.

Peas easily "heat" and spoil after harvest, so keep shaded and well-ventilated. Maintain quality by using forced air to cool to 45 °F (7 °C). Peas cooled below 45 °F may show chilling injury.

One person can harvest 12 to 20 bushels of peas per day if yields are average. Peas are harvested over a 1- to 3-week period. To ensure a continuous supply of peas, space sowing 1 to 3 weeks apart. First sowings may be slower to mature than later sowings because they have experienced cooler growing conditions.

Grading

Pods of similar variety should be fairly well-formed and filled--neither overmature nor excessively young. Pods should be free from decay, worm holes, scars, discoloration, wilting, dirt, or other material.

Peas are graded U.S. No. 1 and U.S. Commercial.

U.S. No. 1--95 percent of the pods must be at least 5 inches long.

U.S. Commercial--No minimum length requirement.

Packing

Summary of Cultural Practices

• Apply any lime needed 3 months before planting.
• Turn under vegetable matter at least 1 month before planting.
• Prepare bed; fertilize and apply preplant herbicide.
• Plant when appropriate for area. Apply any preemergence herbicide used.
• Cultivate and spray at regular intervals four times during blooming. Harvest, grade, pack, cool, and transport.

Production Costs

Tables 3 and 4 should help you work out your production expenses. The pesticides named in Table 3 are used as examples only. Other chemicals cleared for use on Southern peas might be just as effective.

Estimates of harvest labor, packing, and handling are based on a yield of 100 bushels (25 pounds per bushel). You will need to adjust the figures for different yields.

Table 1. Southern pea varieties

Table 2. Chemical weed control in Southern peas

Table 3. Southern peas, fresh market: Estimated costs per acre, Mississippi, 2001.

Table 4. Southern peas, fresh market: Estimated resource use and costs per acre for field operations, Mississippi, 2001.

Table 4. Continued.

Table 4. Southern Peas, fresh market: Estimated resource use and costs per acre for field operations, Mississippi, 1999.

Table 5. Chemical control of insects in Southern peas

Insect	Material	Amount of formulation per acre	Day from last appl. to harvest	Remarks
Aphids and Thrips	Defend 2.67EC	0.75 to 1.5 pt	0	Treat for thrips if you find 3 or more per bloom. There is no indication leaf-feeding by thrips causes any serious damage.
	Diazinon AG500	0.75 to 1 pt	0
	Malathion 5EC	1.5 pt	3
Cowpea Curculio	Thiodan 3EC	0.66 to 1.5 qt	3	First-year peas in some areas may not have a problem with this insect. In areas where peas have grown and/or have a history of curculio problems, sprays should begin when first pods are ½ inch long and continued for 3 to 4 sprays at 5-day intervals.
	Sevin XLR	2 qt	0
Corn Earworm	Lannate 1.8L	1 to 2 pt	1	Treat if you find 1 worm per 3 feet or row. Beet army worm and cabbage looper may be present along with the earworm.
	Nudrin 1.8L	1 to 2 pt	1
	Sevin XLR	1.5 qt	0
Stink bug	Methyl Parathion 4EC	2 pt	15	Treat if you find 2 stink bugs per 10 feet of row.
	Guthion 2S	1½ to 2 pt	7
	Sevin XLR	2 qt	0

This information is supplied for educational purposes only. No discrimination is intended and no endorsement by the Mississippi Cooperative Extension Service is implied.

By Dr. David Nagel, Extension horticulturist, vegetables; Dr. John D. Byrd, Jr., Extension weed specialist; Dr. Frank Killebrew, Extension plant pathologist, now deceased; Dr. J. H. Jarratt, Extension entomologist; and Dr. Tom Jones, Extension agricultural economist.

Publication 1535
Extension Service of Mississippi State University, cooperating with U.S. Department of Agriculture. Published in furtherance of Acts of Congress, May 8 and June 30, 1914. Ronald A. Brown, Director

(rev.500-11-00)