Food & Health
Food & Health
Common Diseases in Field Peas
Mycosphaerella pinodes (Anamorph: Ascochyta pinodes)
Symptoms may appear at any time after plants emergence. On leaves, the disease starts as small purple flecks, developing to dark brown lesion that could dry out the leaves. On stems, lesions are more elongated than on leaves and could potentially girdle the stems. Pods may also be affected later in the season infecting the seeds. Infected seeds may present either no symptoms or shrinkage and dark brown discoloration. Infected seeds can cause foot rot resulting in girdled stems, stunted plants, or plant death.
Moist weather conditions, rain splash, wind, and sprinkler irrigation. Moderate temperatures with daily highs less than 25 °C (77 °C). Leaf wetness for 18 to 24 hours. Dense stands of field peas.
Fusarium solani f.sp. pisi and/or F. avenaceum; Aphanomyces euteiches
Fusarium Root Rot
Reddish brown to black streaks appear on primary and secondary roots. These streaks coalesce at later stages, lower stem is often girdled. Red discoloration of the vascular system can be seen, especially near cotyledon attachment. Stunted growth, yellowing and necrosis appear on the basal foliage.
Soilborne fungi. Cool, wet weather condition before seedling and hot, dry weather after seedling.
Field Pea crop affected by Fusarium Root Rot
Aphanomyces Root Rot
Initial symptoms are often seen on the first primary and lateral roots as honey brown discolorations. As the disease progresses the infected tissues often become soft and darker in color. Plants are easily pulled out of the ground, the cortex often sloughs off and remains behind in the soil leaving the vascular tissue strand attached to the plant. Stunting and wilting plants, yellowing from the bottom upward, and premature death can occur in severe cases.
Favored by poorly drained soil. Often severe when cool wet spring is followed by warm weather.
Field peas affected with Aphanomyces root rot.
Aphanomyces root rot samples: first four rows toward front of picture are non-inoculated pea plants; the last four rows are inoculated with Aphanomyces.
Erysiphe pisi (syn. E. polygoni ),Erysiphe trifolii
Leaves turn light grayish, and powdery on the upper surface of lowest and oldest leaves. Pods are often malformed, small, poorly filled and fall off before they mature. Pod and & stems may turn purplish color. Small black specks, which are fruiting bodies of the fungus, develop in older lesions.
Warm temperature 20-25°C (68-75°F) and humid over 70% relative humidity with overnight dew. Late season or in low, wet areas with high soil moisture. Overwinter on debris and spread by wind.
Pseudomonas syringae pv. pisi and/or Pseudomonas syringae pv. syringae
Small,dark-green water soaked lesions on leaves and stipules. Leaflets turn yellowish and later brown and papery. Lesions on the pods are sunken and turn olive-brown. Discoloration in heavily infected seed.
High rainfals, hail, strong wind and low temperature. Overwinter in debris and is seedborne. Spread through rain-splash or wind-borne water droplets.
Causal Organism: Sclerotinia sclerotiorum
White cottony growth(mycelium) forms on stems and pods. This affected tissue may soften and become slimy. Low areas with increased moisture are often seen affected first. Lodging and bleaching of stems is common. Black hard bodies(sclerotia) are present within the mycelium, stem cavities, pods, and in or on the soil. Affected plants may wilt and die prematurely and contaminated crops could be rejected.
Conditions that favor infection include temperatures of 20-25˚C, moisture, excessive soil nitrogen, heavy seeding rates, planting close together, infected seeds or soil, and using cultivars that produce large amounts of foliage. Also, infected debris and infected fields nearby will increase inoculum source for infection.
For More Information
Links to other websites with information about field pea diseases some of which have been included here:
Informational links for Growing Pulse Crops
Plant Pathology & Plant Disease Management
Pea Seed-borne Mosaic Virus
Common Diseases in Field Peas
Common Diseases in Chickpeas
Common Diseases in Lentils
Root Rot Guide
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Soil Fertility Recommendations
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Growing Pulses in Montana
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