Cotton fields were sampled prior to and after commercial, whole-field applications of insecticides to monitor the effects of insecticides on the densities of beneficial arthropods. The effects of single product conventional chemistry treatments varied somewhat with species of beneficial arthropod, but in general, showed short-lived adverse effects on species impacted. Tracer showed the least adverse effects of all of the products tested. Regent appeared to have rather broad spectrum effects, with longer residual activity than the single product conventional chemistry treatments. The combination of Karate plus Guthion also appeared to have more severe effects, with a longer residual than the single product applications, but this may have been a result of multiple applications rather than the chemistry.

Information on field size, insecticides and rates applied are presented in Table 1. Use rates reflect the producers choice and represent common use rates for the LRGV.

In each field, beneficial arthropods were sampled before and after insecticide applications. Pre-application samples were generally taken the day before treatment, but ranged from the day of treatment (prior to treatment) to three days before treatment. Three post-application samples were targeted at 2 to 3 days after application, 4 to 5 days after application, and 6 to 7 days after application.

Sampling was conducted with a modified leaf blower/vacuum (Sparks and Norman, 1998). Each field was sampled at 6 to 8 locations (generally 8), with 100 feet-of-row sampled at each location. Samples were tagged, transported to the laboratory in an ice chest, and placed in a freezer to kill the arthropods and for storage. Each sample was examined under magnification and beneficial arthropods were counted. Beneficial arthropods and stages sampled were: [names within ( ) indicate the designations used for tabular data]