Plant Disease Management Handbook

Cause The fungi, Fusarium oxysporum f. sp. pisi, races 1, 5, and 6, produce wilt symptoms; race 2 produces near-wilt symptoms. Races 5 and 6 are known to be economically important only in western Washington and southwest British Columbia. Races 1 and 2 reportedly are in all pea-growing regions of Oregon and Washington.

Cause Several fungus-like microorganisms including Pythium aphanidermatum, P. debaryanum, and Globisporangium ultimum (formerly Pythium ultimum) as well as the fungi Rhizoctonia solani, Thielaviopsis basicola, and Phoma medicaginis var.

See:

Pea (Pisum sativum) - Aphanomyces Root Rot

Pea (Pisum sativum) - Seed Rot and Damping-off

Cause Erysiphe pisi (= Alphitomorpha pisi = Ischnochaeta pisi; anamorph Oidium arachidis), a fungus that can be seedborne but usually survives as conidia on living plants. Normally the disease does not cause serious losses if peas are planted in spring or an early-maturing variety is planted. When peas are recropped on the same ground, the fall planting sometimes develops problems.

Cause Eleven reported viruses induce streak symptoms in peas. Alfalfa is the principal inoculum reservoir for streak-inducing viruses in eastern Oregon, eastern Washington, and Idaho. The two viruses that aphids transmit from alfalfa to peas are pea streak virus and alfalfa mosaic virus. Red clover is the inoculum reservoir for the principal streak-inducing virus of western Oregon and western Washington, red clover vein mosaic virus.

Cause The pea seedborne mosaic virus spreads through infected seed. This virus was not known to be in the Pacific Northwest until 1968 and has not escaped into other crop or weed hosts in the United States. The pea aphid (Acyrthosiphon pisum), the green peach aphid (Myzus persicae), and the potato aphid (Macrosiphum euphorbiae) are efficient vectors.

Cause The bean leaf roll virus, which the pea aphid transmits from alfalfa, the overwintering host, to peas. The disease is not seedborne. The disease virtually eliminated susceptible pea lines and varieties in southern Idaho in 1980 and continues to be destructive in irrigated areas of Idaho, Washington, and Oregon.

Cause The pea enation mosaic virus. At least 8 species of aphid can transmit the virus but the principal vector is the pea aphid, Acyrthosiphon pisum. After the aphid acquires the virus, it is 8 or more hours before it can transmit it to a pea plant, but the aphid retains the ability to transmit the virus for at least 24 hours, during which time it can fly or be blown long distances.

Cause The cyst nematode, Heterodera goettingiana, is an aggressive parasite that can be quite damaging to a pea crop. Cysts are the dead bodies of females and may contain up to 300 eggs. Cysts are very persistent in the soil, surviving more than 12 years, and can be spread by moving contaminated soil. Pea and fava bean are the main economic hosts. Certain vetches also can be hosts. Root invasion is promoted by cool soil temperatures (about 55°F).

Cause A fungus-like microorganism, Peronospora viciae (formerly P. pisi), which overwinters on diseased plant refuse in soil. The pathogen has never been shown to be transmitted by seed internally or externally.