Antixenosis of Smooth Leaf Cotton to the Ovipositional Response of Tobacco Budworm1

Abstract

Cottons (Gossypium spp.) ranging from glabrous (Smooth leaf) to Pilose were compared to determine their effects on I he ovipositional response of the tobacco budworm moth, Heliothis virescens (F.). The numbers of trichome branches/cm on the margin, midrib, secondary vein, and petiole., and in an area of the lamina of young fully expanded cotton leaves were positively correlated with the number of eggs laid on cotton plants. Tobacco budworm moths laid fewer eggs on leaves of cottons with no more or fewer trichome branches than those found on ‘Deltapine Smooth Leaf’ than on the normally pubescent cultivar ‘Stoneville 213’ or on the densely pubescent (Pilose) line. Stoneville 213, a pubescent near‐isoline, and a Smooth leaf near‐isoline (Sm2) in Stoneville 213 background, were tested in solid and mixed plantings. Significantly fewer eggs were laid on the Smooth leaf cotton than on the pubescent cottons whether or not the tobacco budworm had a choice of hosts. In a laboratory test, bond paper, synthetic net, rayon, cheesecloth, and muslin fabric were compared in no‐choice and freechoice tests as ovipositional surfaces. Those with textures that had fibers with the highest numbers of loose ends (cheesecloth and muslin) were preferred by tobacco budworm females.