Species composition, damage potential, and insecticide susceptibility of stink bugs in cotton in the Lower Gulf Coast region of Texas.

摘要

Stink bugs have become important pests of cotton, Gossypium hirsutum L., in the Lower Gulf Coast region of Texas. Common species, damage potential, and insecticide susceptibility of stink bugs were assessed. A survey of stink bugs in commercial cotton fields in six counties in the Lower Gulf Coastal region of Texas during 2004 and 2005 revealed that brown stink bug, Euschistus servus (Say); E. quadrator Rolston; and E. obscurus (Palisot) were the most common species (>95% both years), while southern green stink bug, Nezara viridula (L.); and green stink bug, Acrosternum hilare (Say), were less common. This stink bug complex differs from that reported for other areas of the Cotton Belt. Also, significantly more stink bugs were collected in the northern counties of Calhoun, Refugio, and Victoria than in the southern counties of Kleberg, Nueces, and San Patricio (approximately 7.5 and 4 times more in 2004 and 2005, respectively). The potential of E. servus and E. quadrator to damage cotton bolls was compared by caging individual adults on bolls in the field. Both E. servus and E. quadrator caused significant reductions in yield (seed cotton weight) and fiber quality (length and fineness) of cotton bolls. Feeding by both species caused abscission of 1.8-cm-diameter bolls from the plant. In general, E. servus caused more damage to bolls than did E. quadrator and damaged a wider size-range of bolls. Foliar-applied insecticides were evaluated against E. servus, E. quadrator, and N. viridula in small plots of cotton in the field. Dicrotophos was most effective against all species. Pyrethroids killed all N. viridula, but the number of E. servus and E. quadrator killed varied significantly. Euschistus quadrator was more susceptible than E. servus to organophosphate, pyrethroid, neonicotinoid, and carbamate insecticides.