Abstract
Field experiments were conducted in Southampton County, Virginia in 1978 and 1979 on Altavista loamy fine sand (Aquic Hapludult) to determine whether applied nutrients affect the severity of Sclerotinia blight in peanuts (Arachis hypogaea L.) caused by Sclerotinia minor. Soil or foliar applications of N, K, Ca, Mg, P, Mn, Zn, Fe, B, S, and Cl were evaluated alone and/or in various combinations and formulations. Multiple Zn or Cu sprays applied on the foliage suppressed Sclerotinia blight symptoms most during fruit development. Yields in plots sprayed with four 1.12-kg/ha applications of Zn were 1,965 kg/ha greater than in untreated plots in 1978. Four 2.24 kg/ha sprays of Zn increased yields 810 kg/ha in 1979. In 1978, CuSO4 sprayed in a manner similar to ZnSO4 was the second most effective treatment among the simple nutrient materials. Zinc and Cu (sulfates) applied in a multi-nutrient commercial material which also contains Mn, Ca, and P suppressed Sclerotinia blight symptoms nearly as effectively as ZnSO4 sprays. Soil applied Zn or Cu (sulfates) at rates of 22.4 and 11.2 kg/ha, respectively, were relatively ineffective. Sequestrene Cu applied in four 0.56 kg/ha sprays of Cu suppressed Sclerotinia blight as effectively as four 2.24 kg/ha Zn sprays in 1979. Also, Sequestrene Zn and THIS Cu applied similarly to Sequestrene Cu decreased the disease symptoms in 1979.
Molecular diagnosis to identify new sources of resistance to sclerotinia blight in groundnut (Arachis hypogaea L.)
