Effects of fertilizers on suppression of black cutworm (Agrotis ipsilon) damage with Steinernema carpocapsae

The ability of Steinernema carpocapsae to reduce damage to seedling corn by the black cutworm, Agrotis ipsilon, in soil amended with three fertilizers (fresh cow manure, composted manure, and urea) was determined. Total nitrogen was standardized among the fertilizers at 280 kg/ha and 560 kg/ha. Black cutworm damage was assessed by the percentage of cut corn plants in small field plots. Relative to a control (no nematodes), nematode applications resulted in reduced black cutworm damage in all treatments except in the higher rate of fresh manure. Black cutworm damage in nematode-treated plots was greater in plots with fresh manure than in plots without fertilizer. Other amendments (urea and composted manure) did not have a detrimental effect on suppression of the black cutworm by S. carpocapsae.