ABSTRACT

A field test was conducted to evaluate the influence of non-Bollgard cotton refuges on heliothine damage in 2001 and 2002 at the LSU AgCenter's Macon Ridge location of the Northeast Research Station. Embedded non-Bollgard refuge sizes of 48, 24, and 16-rows wide by 160 ft in length were evaluated. In both years the test was sampled after defoliation and before harvest. Heliothine damaged bolls decreased and seedcotton yield increased in Bollgard® cotton as distance increased from a non-Bollgard® cotton refuge. There were 7% and 20% damaged bolls in the refuge and 0.9% and 1.1% in the Bollgard cotton for the 48-row regime in 2001 and 2002, respectively. For the 24-row regime, 5% and 23% damaged bolls were observed in the refuge during 2001 and 2002, respectively. Damaged bolls in Bollgard® cotton of the 24-row regime were 0.7% and 2% in 2001 and 2002, respectively. There were 12% and 20% damaged bolls in the 16-row refuge regime and 4% and 2% in the associated Bollgard cotton during 2001 and 2002, respectively. Lint yield for the refuge of 48-rows was 100 and 350 lb/acre higher in the Bollgard® cotton than the associated refuge in 2001 and 2002, respectively. Estimates of late-season heliothine damaged bolls suggest non-Bollgard cotton refuges are successful in allowing heliothines to develop to late instar stages and potentially add to the local adult populations.