Effects of Planting Date on Thrips (Thysanoptera: Thripidae) in Cotton

Abstract

At-plant applications of insecticides are the most common method to manage thrips in upland cotton, Gossypium hirstutum L. Because the primary pest species, tobacco thrips, Frankliniella fusca (Hinds), has developed resistance to commonly used neonicotinoid insecticides used in producing cotton, alternative control options are needed for sustainable thrips management programs. A 3-year study (2015-2017) showed that densities of thrips, feeding injury from thrips, cotton growth, and yield varied among 10 planting dates. Densities of thrips were lowest in seedling cotton planted after mid-May in all years. Thrips injury ratings in all years were highest in cotton planted in April, lowest in cotton planted in June, and below intermediate injury (intermediate corresponded to a 3 on the 0-5 scale) levels in cotton planted after mid-May. Cotton planted during May, rather than in April or June, had the highest yield potential, regardless of variety. Results of the study indicated that altering planting date could potentially be useful in mitigating injury and losses from thrips in upland cotton.