Effects of Chemicals, Applied Before and After Planting, on Nematodes and Southern Stem Rot of Peanuts. N. A. Minton, Research Nematologist, Agricultural Research, Science and Education Administration, U.S. Department of Agriculture, University of Georgia, Coastal Plain Experiment Station, Tifton 31793. D. K. Bell, Associate Professor, University of Georgia, Coastal Plain Experiment Station, Tifton 31793. Plant Dis. 65:497-500. . This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1981. DOI: 10.1094/PD-65-497.

Phenamiphos applied before planting and ethoprop and phenamiphos (alone or combined with pentachloronitrobenzene [PCNB]) applied after planting significantly increased yields of peanuts. No treatment applied after planting increased yields in plots that had been treated before planting with dibromochloropropane or phenamiphos, indicating that treatment only before planting is adequate to obtain maximum yields. Ethoprop applied only before planting, however, did not increase yields; but when ethoprop was applied before planting and when phenamiphos, PCNB, or PCNB plus ethoprop or phenamiphos was applied after planting, the yield was significantly greater than the yield from plots treated with preplant ethoprop. Yields were negatively correlated (P = 0.01) with root-knot indices (r = –0.47), soil populations of Meloidogyne arenaria larvae (r = –0.20), and Macroposthonia ortatus (r = –0.25) and southern stem rot (r = –0.47). When applied after planting, phenamiphos alone or with PCNB was equal to ethoprop in increasing yields and, when applied before planting, was superior to ethoprop.