Nutritious and able to withstand snow and frost, peas make a hardy addition to vegetable gardens. You can plant them early in the spring or in mid-summer for a fall harvest. Harvest time comes between 55 to 80 days after planting. Having a successful harvest, however, requires recognising and preventing the diseases can afflict your pea crops.
Ascochyta Root Rot - The fungi Ascochyta spp. causes Ascochyta root rot. Purplish streaks form on an infected plant stem above and below the soil. The streaks then grow bigger and extend further up the stem. You can prevent this seed-borne fungus by ensuring you plant disease-free seeds. To manage a breakout of Ascochyta root rot, rotate pea plants every three to five years and use a foliar fungicide.
Bacterial Blight - Bacterial blight, the result of Pseudomonas pisi, infects entire plants, killing affected seedlings. It causes pod damage and green or yellow discoloring, as well as water-soaked spots, which appear on older plants. According to the Penn State Department of Plant Pathology, the bacteria overwinter in the seeds, then spread to the fields via the seeds. Unfortunately, blight has no cure, so you must burn infected plants, as well as surrounding ones, to keep it from spreading.
Fusarium Wilt - The fungus Fusarium causes leaves to yellow and stunts pea plants. Leaflet margins also curl, and the stems look brittle and swollen near the soil line. Pulling up infected plants and burning them works best to prevent the spread of Fusarium wilt. This fungus lives in the soil, so rotating your pea crop the next year is the best way to ensure the next year's crop will not get infected.
Pea Stunt - A virus called red clover vein mosaic will stunt your pea crop. Symptoms of the pea stunt virus include poor pod set, terminal resetting and light-colored veins, in addition to stunted growth. The virus that causes pea stunt actually overwinters in plants of the legume family like alfalfa and clover, then spreads by aphids.
Powdery Mildew - Less destructive than other diseases, powdery mildew (Erysiphe polygoni) can cover the entire pea plant. You can identify it by the powdery white mold that dusts the infected plants. This fungus also causes pea pods to become discolored. Powdery mildew spreads when the wind blows the spores. It especially affects peas planted later in the season and grows in humid--not wet--conditions.