Development of Pink Bollworm Populations (Lepidoptera: Gelechiidae) on Nectaried and Nectariless Deltapine Cotton in Field Cages1

Abstract

The development of populations of pink bollworm, Pectinophora gossypiella (Saunders), on the nectaried cultivar, ‘Deltapine 61’ (DPL-61) of cotton, Gossypium hirsutum L., and a closely related nectariless cultivar, ‘Deltapine NSL’ (’DPL-NSL’), was studied in 0.003-ha screened field cages near Maricopa, Ariz., during the 1986 season. Sixteen cages, eight containing ‘DPL-61’ and eight containing ‘DPL-NSL,’ were inoculated with a total of 25 pairs of laboratory-reared moths in three releases beginning at first Hower buds. Subsequent infestations averaged 6.9 and 12.4 infested (rosetted) blooms per cage for ‘DPL-NSL’ and ‘DPL-61,’ respectively, a nonsignificant difference. Subsequent boll infestations were significantly lower in cages of ‘DPL-NSL’ on three of nine sample dates. Linear rates of increase per day of rosetted blooms and infested bolls were not significantly different for ‘DPL-61’ and ‘DPL-NSL,’ Total catches of male moths in single Delta traps maintained in each cage for 5 wk at the end of the season were significantly lower in ‘DPL-NSL’ (390 males per cage) than in ‘DPL-61’ (525 males per cage). The overall seasonal increases, based on these trap catches, were 15.3-fold for ‘DPL-NSL’ and 21.4-fold for ‘DPL-61,’ a highly significant 29% reduction for ‘DPL-NSL.’