Effect of Placement and Rate of PCNB and PCNB + Ethoprop On The Control Of Southern Stem Rot Of Peanut¹

Pentachloronitrobenzene (PCNB) 10G and PCNB + ethoprop 10–3G applied on 10-cm (narrow) and 25-cm (wide) band widths, respectively, were evaluated for the control of southern stem rot (Sclerotium rolfsii) and impact on yield of peanut. On-farm evaluations with PCNB were done in 1988 to 1990, while PCNB + ethoprop and diniconazole 25W were tested in 1989 and 1990. Narrow band width (10-cm) applications of the 5.6 kg a.i./ha rate of PCNB significantly reduced disease and increased yield all three years compared to the control; the 11.2 kg a.i./ha rate applied on the wide band width (25-cm) reduced stem rot incidence two of three years. The narrow and wide band width applications of PCNB + ethoprop at 5.6 + 1.7 kg a.i./ha and 11.2 + 3.3 kg a.i./ha resulted in reduced southern stem rot incidence and higher yields than the control. Disease control and yield response with PCNB + ethoprop were similar to those in plots treated with PCNB on the narrow and wide band widths. Diniconazole 25W, which was broadcast twice at 0.28 kg a.i./ha in 1989 and 1990, gave better disease control and higher yields than PCNB and PCNB + ethoprop only one of two years.