ARS | Publication request: EFFECTS OF FERTILIZERS ON SUPPRESSION OF BLACK CUTWORM, AGROTIS IPSILON, DAMAGE WITH STEINERNEMA CARPOCAPSAE

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 26, 1999
Publication Date: N/A

Interpretive Summary: Several insect pests of corn are managed using rescue applications of a chemical insecticide. Researchers have, however, developed technology to use a biological control agent, Steinernema carpocapsae to manage the black cutworm. S. carpocapsae is a nematode (a roundworm) that kills insect larvae but does not harm plants or the environment. The nematode can, however, be harmed by certain agronomic practices used in corn production, i.e., nitrogen fertilizer. Therefore, research was conducted to determine the compatibility between nitrogen fertilizer (source and quantity) and beneficial nematodes. High amounts of fresh cow manure were detrimental to nematodes whereas, when smaller amounts of fresh manure and composted manure were used the nematodes effectively stopped cutworms from cutting corn plants. This research provides corn producers an alternative to chemical insecticides which is compatible with organic fertilizers.

Technical Abstract: We determined the ability of Steinernema carpocapsae (Weiser) to reduce damage to seedling corn by the black cutworm Agrotis ipsilon (Hufnagel) in soil amended with three fertilizers (fresh cow manure, composted manure, and urea). 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.