Small plot and large-scale comparisons of stink bug damage to Bollgard and conventional cotton in North Carolina

摘要

To help quantify the impact of stinks bugs, mostly the green stink bug, Acrosternum hilare (Say), on cotton in North Carolina, a series of small plot and large-scale evaluations of stink bug damage to bolls was taken from 1992 through 1999. In the 8 small plot evaluations, stink bug-damaged bolls averaged 2.04 percent in the unprotected Bollgard and 0.36 percent in the pyrethroid-treated conventional plots, or a 5.7-fold greater level of boll damage in the Bollgard plots. In a state-wide survey of stink bug damage to bolls, undertaken from 1989 to 1195 (n =1620 cotton fields) stink bug injury on conventional cotton ranged from 0.20 percent to 1.17 percent, with a mean of 0.56 percent, while boll damage in Cleveland County, a county of limited insecticide use (similar to that required for Bollgard cotton), ranged from 1.67 percent to 8.50 percent, with a mean of 3.86 percent. In a 1996 through 1999 large-scale evaluation of 366 pairs of Bollgard and conventional cotton fields managed by cotton producers, the Bollgard cotton fields averaged 2.60 percent boll damage and 0.74 insecticide applications, while the conventional cotton fields averaged 0.61 percent boll damage and 2.53 insecticide treatments. Thus, the Bollgard fields' showed approx, a 4.3-fold higher level of stink bug damage, and the conventional cotton required 3.4 times the number of insecticide treatments, primarily for bollworm control. Seventeen untreated Bollgard varieties showed a wide range of boll damage from stink bugs (1 percent to 20 percent) in a small plot replicated trial, although no correlation was found between maturity and boll damage.