Bionomics of Cotton Thrips: A Review

Abstract

This is a review of selected world literature on thrips of cotton, with emphasis on the major pest species. Thrips inhabiting cotton plants include bud (grass and flower) and leaf feeders, and predatory species. Bud feeding thrips inhabit the growing tips of pre-flowering cotton causing distorted growth. This group may be most apparent on seedling cotton, but persists through the growing season. Both adult and immature stages of leaf feeding thrips inhabit older leaves and frequently defoliate plants. Predatory thrips attack infestations of spider mites, thrips, and whitefly and usually become abundant in late summer. Bud thrips are most common on cotton in arid to semiarid regions. Abundance is strongly influenced by availability and condition of alternate hosts, and infestations are suppressed by frequent or timely rainfall. Several of the bud dwelling species are facultative predators on spider mite eggs, hence seasonal time of occurrence may make this group of thrips a major element in the biological control fauna of cotton fields. Management decisions for cotton should consider thrips abundance, projected heat unit accumulation during the seedling stage of plant growth, potential benefit of spider mite predation, and availability of effective insecticides.