Indole-Acetic Acid and the Ethylene Precursor, Acc, in the Cotton Fleahopper (Hemiptera: Miridae) and Their Role in Cotton Square Abscission

Abstract

Indole-acetic acid (IAA) was present in laboratory-reared nymphal and adult cotton fleahoppers, Pseudatomoscelis seriatus (Reuter). The ethylene precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), occurred in nymphal and adult cotton fleahoppers reared in the laboratory and in nymphs collected from the host plants croton, Croton capitatus Michaux; horsemint, Monarda punctata L.; and cutleaf evening primrose, Oenothera laciniata Hill. Cotton fleahopper eggs did not contain ACC. IAA and ACC, when injected into cotton shoot tips at concentrations occurring in cotton fleahoppers, induced ethylene production to levels higher than in controls but lower than in terminals infested with cotton fleahoppers. Thus the IAA and ACC in cotton fleahoppers may contribute partially to the mechanism by which cotton fleahoppers promote ethylene-mediated abscission of cotton flower buds.