S. Hague

Cotton Square Morphology Offers New Insights into Host Plant Resistance to Cotton Fleahopper (Hemiptera: Miridae) in Upland Cotton.

Abstract Cotton fleahopper, Pseudatomoscelis seriatus (Reuter) (Hemiptera: Miridae), is a piercing–sucking pest of cotton (Gossypium hirsutum L.) that feeds preferentially on developing flower buds, called squares. Heavy infestations cause yield reductions that result from abscission of squares damaged by the cotton fleahopper feeding. Antixenosis, or nonpreference, has been reported as a mechanism of host plant resistance in cotton to cotton fleahopper. Square structure, particularly the placement of the reproductive tissues, and stylet penetration were investigated as factors that influence resistance to cotton fleahopper in cotton lines derived from crosses with Pilose, a cultigen of upland cotton resistant to cotton fleahopper, and backcrossed with high-yielding, susceptible lines. Ovary depth varied among the lines tested and was found to be a heritable trait that affected the ability of a fleahoppers feeding stylets to penetrate the reproductive tissues in the square and might influence preference. Behavioral assays suggested antixenosis as a mechanism of host plant resistance, and the trait conferring antixenosis was found to be heritable. Results suggest ovary depth plays a role in conferring resistance to cotton fleahopper and is an exploitable trait in resistance breeding.

Evaluating Pilose, a Cultigen of Gossypium hirsutum, as a Source of Resistance to Cotton Fleahopper (Hemiptera: Miridae).

ABSTRACT Cotton fleahopper (Pseudatomoscelis seriatus Reuter) (Hemiptera: Miridae) is a piercing—sucking insect that has emerged as a major pest of cotton (Gossypium hirsutum L.) in Texas. Cotton fleahoppers feed on floral buds, commonly referred to as squares, causing damage and abscission, and subsequent yield loss. Previous studies indicate that plant resistance to cotton fleahopper is present in upland cotton, but the mechanism of resistance remains undetermined. In this study, Pilose, a cultigen of G. hirsutum, was examined as a source of resistance to cotton fleahopper, focusing on mechanism of resistance and heritability of the resistance trait. Results indicated that the resistance trait in Pilose is heritable and that pubescence is causative of resistance or that the resistance trait may be tightly linked to genes controlling pubescence. Behavioral assays indicated nonpreference as a mode of resistance in plants with dense pubescence.