Revision Date: 5/6/2004 Dewey Caron, Extension Entomologist Bob Mulrooney, Extension Plant Pathologist Ed Kee, Extension Specialist Derby Walker, Extension Agent HG-13 Peas and Beans Peas and beans are members of the legume family. Legumes produce their own nitrogen through nitrogen fixing bacteria, Rhizobium found on the plant roots. They grow best in soil that is only slightly acid (pH 6.0-6.5). Because peas and beans are very susceptible to root rot, they should also be planted in well-drained soil. These crops require very little fertilizer in most gardens. For a new garden, 1-1/2 pounds of 10-10-10 per 100 square feet is adequate. For a well-established and tended garden, 1/2 pound of 10-10-10 is more than enough. Peas are a cool-season vegetable that should be planted in early March to April. They can be planted in a single row, but grow best planted in double rows. Plant peas 6 inches apart with 30 inches between the double row. One option is to set up a fence of chicken wire, or similar material, between rows to support the peas. This keeps them off the ground and reduces bird damage. Peas are at their highest quality when harvested just before the pod is full but still firm with tender peas. Cook or blanch peas immediately after harvesting. Harvest the edible pod or sugar pod type of peas before the pea seeds are clearly visible. The major problem in growing peas in Delaware is root rot. Root rot can be controlled by rotating the planting site and selecting a site with well-drained soil. Birds also love peas because the pea crop is one of the earliest available to feed their young. The best control against birds is netting. Peas present few insect problems. On occasion aphids can be found on peas. Wash or rub these off since infestation will be localized and insects will be grouped together. Malathion, insecticidal soap, endosulfan, esfenvalerate, pyrethrins, neem oil, hot pepper wax ( repellant) can be used if the infestation is heavy. Seedcorn maggots in soil can prevent seeds from germinating. Just replant. Armyworms or earworms may be found in peas during heavy worm years. Carbaryl, pyrethrins, spinosad, neem oil, esfenvalerate, azadirachtin insecticide or handpicking are effective controls. String beans can be planted from April 15 until about August 8. Many people like several small plantings of snap beans in order to have fresh beans all summer. If you plan to can or freeze a quantity of snap beans, make your main planting early to reduce problems with worms and heat. Heat causes the blossoms to drop off. It also makes it uncomfortable for the gardener to harvest and process the vegetables. Plant bush-type snap beans in rows 2 to 3 feet wide with 2 to 3 inches between plants. Many of the new varieties of snap beans are more tender and http://ag.udel.edu/extension It is the policy of the Delaware Cooperative Extension System that no person shall be subjected to discrimination on the grounds of race, color, sex, disability, age, or national origin. less stringy than old varieties. These varieties also offer good disease resistance: Provider, Gator Green, Tender Crop, and Blue Crop. While pole snap beans aren't difficult to grow, most gardeners prefer bush beans because they require less room and less work. Good pole bean varieties include Kentucky Wonder, Kentucky Wonder 119, and Bluelake strains. Lima beans require warm soil. Don't plant lima beans before May 10. In fact, in some years, wait until May 15 because of cold, wet soil. Often home gardeners put in only one planting, but lima beans can be planted from May 15 to July 15, depending on the location. Limas should be harvested before the seeds are fully developed and have begun to dry. The favorite bush-type variety of lima is Fordhook 242. Good baby lima varieties for Delaware are Bridgeton, and Cypress. Pole beans are the most popular lima beans grown in Delaware. These should be planted in May. Vines are trained to either wires or poles from 6 to 9 feet in length. Many popular local varieties are available; commercial varieties include King of the Garden and Burpee's Best. Spider mites are the major pest of pole beans. Some gardeners may want to try edible soybeans, which are nutritious because of their high protein content. They can be used as a fresh green bean, dried and roasted as a nut, or ground into flour. Plant soybeans mid-May and mid-June. Plant soybeans in rows 2 to 3 feet apart, with plants spaced 2 to 3 inches apart. Diseases and Insects Bacterial Blight Bacterial blight is one of several bacterial diseases that infect snap beans. Bacterial blight appears as translucent water-soaked spots, which with age turn red around the rims. Bacterial blight is seed-borne, so using disease-free seed is an important preventative step. Anthracnose This fungal disease appears as circular, dark, sunken spots on pods and stems. The fungus overwinters in the seed and in bean refuse. Spores are scattered from plant to plant by wind, rain, and people working in the garden, especially when the foliage is wet. To control, use disease-free seed and allow two years rotation between bean plantings. Rust Bean rust is a disease chiefly of the leaves. Symptoms appear as powdery red or black pustules about the size of pinheads. High humidity favors development of this disease. Rust is only a problem in the late summer and fall. Plant-resistant varieties are one solution. Spray with chlorothalonil when disease first appears. Root Rot Root rot fungi survive in the soil from year to year, so rotation is very important. Most root rot fungi are favored by cool weather and high soil moisture content. For beans, delay planting until soil temperature is 60 F or higher. . Downy Mildew Downy mildew is a problem for lima beans mainly in the fall. It can cause severe losses, especially in wet seasons. Downy mildew appears as white, cottony growth, mainly on pods, but it also attacks young shoots and flowers. Infected pods eventually shrivel, die, and turn black. Tri-basic copper sulfate will help if applied at the first sign of disease. Bean Mosaic Viruses Bean mosaics cause stunted plants and mottled and malformed leaves. Infected leaves are usually irregularly shaped, with light green and light yellow areas of various sizes. Pods of bean plans can also be seriously deformed. The yellow bean mosaic virus is transmitted by aphids from nearby gladiolus flowers, so it is important to control aphids and use mosaic- resistant varieties. Controlling Bean Diseases Since many of these troublesome diseases are seed-borne, it is important to use disease-free certified seed. Don't save your own seed from season to season. Avoid working in the garden when the foliage is wet; diseases are easily spread in this way. Crop rotation, planting resistant varieties, and properly timed use of recommended fungicides are helpful methods of control. Insects The most troublesome insect on beans is the Mexican bean beetle (order Coleoptera). The adult is copper-colored with 16 black spots; larvae are yellow, spiny, and soft-bodied and lay a cluster yellow eggs normally under the leaf. The eggs, larvae and adults can all be hand removed and crushed. Feeding is generally from the underside of the foliage. This causes a characteristic skeletonizing in which the veins remain but tissue between the veins is removed. If Mexican bean beetle numbers are high and damage is evident spraying with Carbaryl, neem oil, azadirachtin, or esfenvalerate maybe warranted. Aphids (order Homoptera) can be a problem in beans as well as in peas. Use a stream of water or rub off aphid colonies with your fingers when you find them on the stems. Use an insecticide ( see Peas above)if the infestation is heavy. But this may necessitate a timed spray because natural enemies will be killed, and the pest aphids will recover more rapidly than the natural controls. Seedcorn maggots (order Diptera) are a problem for early-planted bean seeds. Seeds fail to germinate and row stands may be thinned. Since beans are commonly planted heavily, this is not always a problem. Replant if too few plants germinate. To confirm that germination failure is insect related, dig up the seeds to examine. The maggot will be inside the seed or curled up around it. Other pest problems of beans include bean leaf beetles, flea beetles, stink bugs, leafhoppers, and spider mites. These can be controlled with properly timed sprays. Approved insecticides for general use may offer some measure of relief. Sometimes early-season insecticide use aggravates spider mites, which require hot, dry weather to reach pest status. Caterpillars such as armyworms, corn earworm, and European corn borer may be numerous enough to cause damage on fall beans. They feed on or in the pods. If infestations are heavy, pick the caterpillars off or use a dust. There is no control once caterpillars are feeding inside pods, so for best control, check the pods as they are filling. . Pesticide products included in this publication are generally listed as "active ingredient." The active ingredient is the material in the formulation that has the pesticidal activity. You will need to read the pesticide label on to determine if they contain the appropriate active ingredient. Regardless of the insecticide you choose, be sure the type of plant you want to spray and pest you want to control is listed on the label. Disclaimer: Mention or exclusion of any product is not intended to discriminate for or against any products. No endorsement is intended for the products mentioned, nor is criticism meant for products not mentioned. Please read labels before purchasing and then read them before using to ensure that target sites are listed .