Seven Years ofSclerotium rolfsiiin Peanut Fields: Yield Losses and Means of Minimization

Yield losses in peanut (Arachis hypogaea) caused by southern stem rot were evaluated in growers’ fields at 44 individual sites over a 7-yr period from 1983 through 1989. Differential disease levels were obtained through different levels of infestation among sites and applications of pesticides, including PCNB, chlorpyrifos, ethoprop, diniconazole, tebuconazole, propiconazole, and fonofos. Peanut yields were reduced by 2.9 or 0.9% for each locus or “hit” of southern stem rot disease per 30.5-m row; losses were greater when the crop was stressed by high temperatures. Yields of untreated plots averaged 785 kg/ha less than those of plots receiving the best treatments. Yield potential was shown to be greater with the use of newly developed pesticides and fungicide/insecticide combinations than potential estimated from loss models developed 20 yr ago