Earlier reports and updates of the PEG-US program for monitoring resistance to the pyrethroid insecticides in Heliothis/Helicoverpa populations across the US Cotton Belt have been presented at Beltwide Conferences by Riley (1988), Staetz (1987), Rogers (1990) and Mullins (1991). Additionally, three papers were presented by PEG-US at the 1988 Beltwide Conference in which resistance assays involving several life stages of Heliothis virescens were discussed. These included; adult vial tests (D.E. Simonet), first instar foliar tests (M.D. Collins) and larval topical tests (C.A. Staetz).

The PEG-US Committee was formed at the 1987 Beltwide Cotton Conferences - Volume 2 in Dallas, TX and embarked on a coordinated Heliothis virescens monitoring program across the US cotton producing region as one of the committee's first projects. The adult vial test (AVT) developed by Dr. Bill Plapp of Texas A&M University has been used extensively in this program with back-up laboratory larval tests to confirm the AVT results. To date, emphasis has been on Heliothis virescens because of the resistance already documented in that species when PEG-US was formed in 1987. The response of Helicoverpa zea is also being monitored for any development of resistance to pyrethroids. This could pose an even greater threat to US cotton production. Cooperation with University Research and Extension personnel and Agricultural Consultants has played a key role in developing the data base generated by this research and in the development of resistance management programs.

This paper summarizes the 1991 Heliothis/Helicoverpa monitoring results and compares these with earlier data.