Greenhouse Thrips Screening to Support Development of Cultivars for Organic Cotton Production

Thrips are one of the most serious early season cotton pests on the Texas High Plains. Heavy infestations in the early stages of cotton growth, from the 1st to 5th true leaves, can cause significant injury to seedlings, often resulting in serious economic loss. Infestations in organic cropping systems can cause more difficulties due to the lack of effective, organic-approved pesticides. Thrips problems may also become more common in conventional cropping systems as the supply of aldicarb, a common pre-emergence systemic pesticide, is exhausted. Texas A&M Agrilife Research Station in Lubbock, Texas, is conducting ongoing research to develop naturally occurring host plant thrips resistant cultivars for use in organic production systems. In 2009, a large, greenhouse screening test was initiated to evaluate thrips resistance of breeding lines selected in field trials for early emergence and cold tolerance. The experiment screened 14 cold tolerant lines alongside susceptible and resistant controls. The lines were phenotyped using leaf surface area reduction, a visual injury rating, and thrips numbers. Four lines were selected from this evaluation and previous field performance trial to use as parent lines for cultivar development.