Pink Bollworm Resistance in Cotton1

Abstract

Experiments were conducted during 1953-55 at College Station, Texas, to determine if selected species and varieties of cotton were resistant to pink bollworm ( Pectinophora gossypiella (Saund.)) damage. Results of these experiments indicated that Gossypium thurberi was resistant to pink bollworm attack. The mechanism of resistance appeared to be preference of the moth for other cottons for oviposition. Evaluation of the various experiments indicated that this nonpreference for G. thurberi was caused by morphological characters of tight smooth calyx, spike-like flared brads and glabrous vegetative parts of the plant. A cross of Stoneville 2B × G. tomentosum showed a high degree of antibiosis to pink bollworm larvae. Hexaploid Z-64 and G. thurberi and G. herbaceum exhibited antibiosis to lesser degrees. No evidence of resistance was noted in the Old World species of G. arboreum and G. herbaceum . Results obtained in the various experiments conducted indicated that modification of certain morphological characters of the cottom plant may result in better control of the pink bollworm. The use of a cotton that has flared or deciduous bracts, tight smooth calyxes, and more pubescence on the vegetative parts should result in most of the eggs being laid on the vegetative parts. Higher natural mortality and increased effectiveness of applications of insecticides should result from the increased exposure of the pink bollworm larvae.