Breeding Cotton for Resistance to the Tobacco Budworm: Techniques to Achieve Uniform Field Infestations 1

Techniques, equipment, and procedures for handling tobacco budworm, Heliothis virescens F ., pupae, adults, eggs, and first instar larvae are described, as well as procedures for uniformly distributing first instar larvae on progeny rows of cotton ( Gossffpiurn hirsutum L .) in field plots. These techniques provide the uniformity and damage levels necessary to evaluate progeny rows for resistance to the tobacco budworm. In 1980, the techniques were used for 8 weeks. Egg production averaged 220,000 per day; and 90,000 to 100,000 plants were inoculated seven times each over the 8‐week period. To illustrate the effectiveness of the techniques, data for the two check entries from 25 experiments are included herein. Mean yield losses due to Heliothis were 1,514 and 1,563 kg seed cotton/ha in ‘Stoneville 213’ and in a glandless, nectariless line of ‘Stoneville 7A,’ respectively. The system described is cost effective, rapid, uniform, and can be expanded easily to any desired size. The availability and use of these techniques should make it feasible for commercial cotton breeding companies to evaluate and select lines with increased levels of plant resistance to the tobacco budworm