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Problem
(factsheet)
Plant NameTypeDescription 
Aphanomyces root rotPeaDiseaseAphanomyces root rot is caused by a fungus which attacks the underground portions of the plant. The lower stem and roots initially show long, soft, water-soaked lesions which can spread throughout the root system, affecting the outer portion of the roots (cortex). The cortex tissue softens and turns dark brown before it dies and sloughs off. Above ground, the plant is yellowish and stunted, produces few or no pods, and eventually dies back. Root rots tend to affect plants in low-lying areas and in soils with poor drainage. The fungus persists in the soil for many years even when host plants (peas, alfalfa, beans) are not present.
Pea wiltPeaDiseasePea wilt is caused by a fungus. Several races of the fungus occur and may cause different symptoms. Typically, plants are yellow, stunted, wilted, and often die. Plants affected by races 1, 5, and 6 may show downward curling of leaves and stipules. Stems are more rigid and brittle than uninfected plants. These plants may also show a yellowish to orange discoloration inside the lower stem and the root system. The root system otherwise appears normal. Race 2 causes a disease known as "near wilt". The general symptoms are similar to those described. In addition, foliage may show a grayish discoloration and the disease may result in yellowing and wilt of the plant. The internal discoloration caused by Race 2 is typically dark red. The root system of affected plants may show some decay.
Powdery mildewPeaDiseasePowdery mildew is a fungal disease which attacks the leaves, pods, and stems. Leaves and stems develop discolored spots. The spots later show characteristic white mats of powdery fungal growth which give a bluish cast to the foliage. Small black fruiting bodies of the fungus may be present in the white mats. The infected areas may die on some pea varieties, and some varieties including 'Oregon Sugar Pod' may show brown or black necrotic spots on affected pods. Infection early in the season may result in stunted plants. Powdery mildew may result in reduced yields. Warm days, cool nights, and humid weather favor development of powdery mildew, which is often worse in the fall. The fungus may be carried by infected seed, which is often gray-brown in color. It can also overwinter on infected plant debris.
Root rotPeaDiseaseSeveral fungal root rots can affect peas. Typical symptoms of root rots are stunting, yellowing, and dieback of aboveground portions of the plants. Root systems of affected plants are smaller than normal. Variously-colored lesions (red, black, grayish) are present on the roots, and the root system eventually becomes black and rotted. Aphanomyces root rot causes straw-colored lesions on the roots. Fusarium root rot causes red streaking in the core of the main root and lower stem. Other root rots do not cause this unique discoloration.
Seed rot and damping-offPeaDiseaseSeveral soil-borne fungi can cause seed rots and damping-off of pea seedlings. Infected seeds decay without germinating. Seedlings may be infected and fail to emerge from the soil. Emerged seedlings are also attacked, causing them to wilt and topple over. Water-soaked or brown to black lesions are often visible on the stem at the soil line. Plants become more resistant to attack as they mature. Damping-off fungi are more of a problem in cold soils with poor drainage, and in conjunction with overwatering.
Virus diseasesPeaDiseaseSeveral virus diseases affect peas. Pea Enation Mosaic Virus, Pea Seedborne Mosaic Virus, and Pea Streak Viruses are viruses of importance in Washington. These viruses are spread by aphids including the pea aphid. Pea Seedborne Mosaic Virus is also carried by infected seed. Pea Enation Mosaic Virus causes mottling, stunting, and enations (small bumps or blisters) on leaves. Pods and leaves may be distorted. Pea Seedborne Mosaic Virus causes pod distortions and stunting, rosetting, and rolling of leaves. Leaves and pods appear mottled, and infected seeds may have a brownish stain or discoloration. Pea Streak Viruses cause brown to purple spotting or streaking on leaves, stems, or pods and result in rapid death of plants. The viruses affect many hosts in the pea family (Leguminosae). Alfalfa, clovers, and weeds can serve as sources of infection.
Brown marmorated stink bugPeaInsectThe brown marmorated stink bug (BMSB) is an introduced pest species from Asia that is spreading quickly across the United States. Nymphs and adults feed on a wide variety of plant hosts. BMSB prefers to feed on fruit, seeds, and seed pods, but will also feed on stems and leaves of some hosts. Both adults and nymphs have piercing-sucking mouthparts and inject digestive enzymes into plant tissues to aid in feeding. BMSB damage can appear as discolored, sunken lesions on the surface of the pea pod. Inside the pod, whitish or brown spots develop and seeds may be deformed, shriveled or fail to develop. Secondary damage from rot may occur at the feeding site. Other known vegetable hosts of BMSB include tomatoes, peppers, corn, and cucumbers. One or two generations of BMSB per year are expected in the Pacific Northwest. Adults overwinter in sheltered locations (including houses, where they can become a significant nuisance pest). In the spring, light green to white eggs are laid in groups of about 20 to 30 on the underside of leaves. Young stink bugs, or nymphs, are black with a red-and-black striped abdomen. Nymphs often feed in groups when young. Older nymphs are dark with white bands on body, legs, and antennae. They may feed in groups or singly. Adults are a little over 1/2 inch long, with a shield-shaped body. Body color on adults is mottled gray and brown, while the legs and antennae have alternating dark and light bands. The abdomen also has dark and light bands which are visible at the edge of the wings. NOTE: BMSB adults closely resemble other stink bugs found in WA and OR. For more information on BMSB identification, see FS079E, Pest Watch: Brown Marmorated Stink Bug, available at https://pubs.wsu.edu/.
Cutworms and armywormsPeaInsectCutworms and armyworms are the larvae of noctuid moths. These common moths are medium-sized with fairly dull coloration. Several species may feed on peas. The greenish, grayish, or tan caterpillars are hairless, nocturnal, and generally spotted, striped, or otherwise marked. They may be 1/4" to 1" in length and tend to curl up when disturbed. Cutworms often feed by cutting through stems of young plants an inch or less above ground level. Several seedlings may be damaged in one night. They may also climb into the plant and feed on foliage and chew holes in developing pods. While armyworms typically feed during the day, cutworms spend the day just beneath the soil surface or under debris near the host. They usually feed at night, so it is advisable to search for them with a flashlight in the dark. Weeds are their primary food source.
Pea aphidPeaInsectThe pea aphid is a green to pinkish, pear-shaped, soft-bodied insect. It is usually found feeding in large colonies on the stems and undersides of leaves near the tips of new growth. Aphid feeding may cause foliage to turn yellow and wilt. Foliage may also be curled, mottled, and deformed as a result of infection with the Pea Enation Mosaic Virus transmitted by the aphids. Feeding aphids also secrete honeydew, a sweet, sticky material which may attract ants or become covered with sooty mold. Honeydew-feeding ants may protect aphid colonies from predators.
Pea leaf weevilsPeaInsectThe pea leaf weevil is a small brownish-gray beetle about 1/5" long. Adults are marked with lighter longitudinal lines on the back. They feed on the leaves, cutting out semicircular pieces from leaf margins. Damaged leaves appear ragged. Severe infestations may result in complete defoliation, particularly of young plants. The curved white larvae have dark heads and are found in the soil. Pea leaf weevils also feed on vetch, clover, and alfalfa.
Pea MothPeaInsectThe pea moth, Cydia nigricana, is a “sometimes” pest of the homegrown peas. Its presence is rarely detected until the gardener begins to harvest mature peas. At this time, as the peas are shelled, it becomes obvious that if present – a yellowish white caterpillar about ½ inch long at maturity, has been dining on the seeds. Evidence of its past presence includes the obvious emergence hole in the side of the pod, copious excremental pellets (or frass), and irregular cavities in the seeds themselves. Affected pods become yellow or ripen prematurely. The larvae spend the winter in a silken soil cocoon found just below the soil surface. They pupate in the late spring. Sometime in the growing season (exact time coincides with heat unit accumulations), the adults emerge, mate, and lay individual eggs on blossoms, stems, leaves, or pods. Pea moths attack peas, sweet peas, and vetch. At hatching, the young larvae burrow through the pod leaving a small, almost undetectable entry hole. After 2-4 weeks, the larvae leave the pod to seek an overwintering site in the soil.
SlugsPeaInsectSlugs are common garden pests in western Washington. They resemble snails, but lack shells. They may vary in length from as little as 1/4" up to several inches in length, depending on age and species. Foliage of older plants is raggedly chewed, while younger plants may be totally consumed. Slugs leave behind a characteristic slime trail, which appears silvery when it dries. Slugs typically feed at night and do more damage during cool, moist weather.