Limb rot usually appears in late August and September after the vines of runner varieties
have lapped. Elongated spots (lesions) develop on the underside of lower branches
in contact with the soil. The lesions are dark brown and may have a target-like appearance.
Lesions expand and girdle individual branches causing them to wilt and die. Several
branches may be killed, but generally not entire plants as with Sclerotinia and southern
blights. In severe cases where rainfall is excessive, leaves within the canopy are
covered with a white, moldy growth. In addition to causing pod rot, the fungus also
may infect the tips of pegs as they penetrate the soil. The pod-forming region of
infected pegs is killed, turns black, and appears shredded.
Please contact your local county extension office for current information.