Morphological and molecular survey of thrips in commercial snap bean and lablab fields in south Florida

Megalurothips usitatus Bagnall (Thysanoptera: Thripidae), an invasive thrips first reported in Florida in March 2020, is an economically important pest of snap beans (Phaseolus vulgaris) and lablab beans (Lablab purpureus) grown in south Florida. Thrips palmi is also a significant economic pest of snap beans. Identification of thrips species based on morphology can be challenging for the non-specialist. Molecular methods provide a greater level of precision and allow reliable identification in all growth stages. This work aims to develop taxonomic and molecular tools to improve the accuracy and speed of identifying invasive and endemic thrips species associated with legumes of economic importance to Florida. To determine the distribution of thrips, surveys were conducted in 20 commercial fields (6 lablab and 14 snap bean fields) distributed in Miami-Dade and Hendry Counties. For each site, 20 flower samples were randomly collected to determine the abundance of thrips species. The total number of adult and larval thrips per flower was counted, and thrips adults were morphologically identified. Twenty specimens of each species were molecularly identified based on the mtCOI gene. Mixed populations of M. usitatus, Frankliniella insularis, and Thrips palmi were found in snap bean and lablab beans in Miami-Dade County, and M. usitatus, F. schutzei and F. bispinosa were found in snap bean in Hendry County. All specimens are slide mounted and an open-access database platform is being created with molecular and morphological data. Improved diagnostic tools for these species will be a valuable resource for managing thrips in Florida and elsewhere.