Field Trials of Aerosol Formulations of Avermectin Bl, 1991

Abstract

Abstract Field tests were conducted on the relative efficacy and residual life of two aerosol formulations of avermectin Bl. The Dorie Miller Homes, Duneland Terrace, and Broadway Village, multi-family public housing complexes located in Gary, Indiana, served as the test sites; individual apartments served as the replicated experimental unit. All applications were made with readyto- use aerosol cans containing formulated active ingredients. Bait was applied generously throughout the apartment, focusing attention on the cracks and crevices harboring infestations of cockroaches. Some general surface treatments were made at the intersections of shelves and cabinetry, or floors and walls (particularly around the stove and refrigerator). All obvious harborages (i.e., cracks in walls, along and behind baseboards, beneath and behind sinks, stoves, refrigerators and cabinets, around plumbing and other utility installations) were treated, as well as infested furniture and the inside of cabinets and closets. The amount of bait applied in each apartment was recorded for analysis. Population levels were estimated by visual counts throughout the kitchen and bathroom areas, and a minimum pretreatment count of 20 cockroaches was required for any apartment to be considered as a test. Each treatment was replicated in 11-14 apartments, but posttreatment counts varied due to apartment vacancy or lack of resident cooperation. To determine insecticidal efficacy, posttreatment visual counts were reduced to percentage of reductions of the pretreatment counts. Prior to statistical analysis, percentage of reduction data were transformed to ranks. All data were analyzed with ANOVA models; followed by the F-statistic (P = 0.05) to determine significance between the treatments at each posttreatment census.