Description

Abstract: Selected prophylactic applications of granular insecticides were evaluated during 1985, 1986, and 1987 in North Florida for efficacy against lesser cornstalk borer (LCB), Elasmopalpus lignosellus (Zeller), effects on peanut seed yield and quality, and net economic return. Chlorpyrifos 15G, ethoprop 15G, and fonofos 10G were applied as band treatments over the row at various rates and times during the growing season. Dichloropropene was applied for separation of nematode effects alone and in combination with selected insecticides as an injection treatment 6 or 7 days before planting. Mean percentage of peanut plants infested with LCB larvae did not exceed 5% in any treatment, including the control, in any year. Mean densities of emerging LCB adults estimated from over-the-row wire traps did not exceed 1.2. moths per meter of row from early flowering until one month after scheduled harvest in any treatment during the study. No differences in LCB densities were detected among treatments. However, several treatments significantly improved peanut seed yield or quality in individual years and resulted in economic returns greater than the costs of treatment.