Investigating the thrips species complex in the major strawberry growing area of Florida

Thrips (Thysanoptera) are pests of a number of commercially grown crops in the state of Florida. There are a number of pest thrips species belonging to the subfamily Thripinae in Florida including Frankliniella bispinosa, Frankliniella occidentalis, Frankliniella tritici, Frankliniella schultzei and Scirtothrips dorsalis. In 2013, some strawberry growers in the major growing areas experienced failures for thrips control despite frequent pesticide applications. At that time not much was known about thrips abundance in the system; monitoring was conducted during the 2013-14 growing season. The objective of the study was to investigate thrips species complex associated with strawberries in the major growing region to determine the plant part that was affected and to quantify the thrips species found. Leaf and flower samples were collected from 16 commercial farms (15 conventional and 1 organic) in Hillsborough County, Florida every 14 days for 2 months. Samples were taken to the University of Florida Small Fruit and Vegetable IPM Lab and counted under a stereoscope, and the data analyzed. The number of thrips found in flower samples was significantly higher than those found in leaf samples. The main species found were F. schultzei, F. occidentalis and F. bispinosa in both flower and leaf samples. The dynamics of the thrips population and composition changed with time. Knowing the species of thrips that are present in this system is important in developing IPM programs to manage thrips in strawberries in Florida and to minimize the possibility of chemical resistance in the thrips population.