DAMON SMITH, UNIVERSITY OF WISCONSIN-MADISON, BUGWOOD.ORG
Sclerotinia blight is known by the tan lesions and the cottony white mycelium that puff out on the stems.
Which Will It Be? Sclerotinia blight or Southern stem rot — depending on the weather, one of these is likely in Virginia fields. By Amanda Huber
V
irginia producers find primarily three diseases in their peanut fields, says David Langston, plant pathologist at Virginia Tech’s Tidewater Agricultural Research and Extension Center. “Most fungicide sprays are targeted to leaf spot, Sclerotinia blight or Southern stem rot.” However, based on weather conditions during the season, producers are likely to only encounter leaf spot and one of the other two. If weather is favorable for Sclerotinia blight, then it is not the hotter sometimes dryer weather preferred by Southern stem rot. Record Disease Levels Langston says, “Typically, severe outbreaks of stem rot and Sclerotinia blight don’t co-exist. “In 2020, we saw a good bit of late leaf spot and Sclerotinia blight in our plots. 12 /
THE PEANUT GROWER • MAY 2021
In contrast to Sclerotinia blight, the white mycelium growth of Southern stem rot, or white mold, is closely pressed to the stem.
“Cooler-than-average temperatures beginning Labor Day created very favorable conditions for Sclerotinia blight. The Virginia Sclerotinia Blight Advisory indicated that the risk of disease development was high from Aug. 2 until Oct. 17. PEANUTGROWER.COM
