Monday, December 11, 2006 - 8:59 AM

Field dispersion and hot-spot formation of flower thrips, Frankliniella spp. (Thysanoptera: Thripidae), in early-season blueberry fields

Hector Alejandro Arevalo, and Oscar E. Liburd, University of Florida, Entomology and Nematology Department, Bldg. 970 Natural Area Drive, Gainesville, FL

Florida and southern Georgia are the only producers of early-season blueberries (April - June) in the world. The areas cultivated with early-season blueberries increased 35% over the last three years, making this type of blueberries one of the fastest growing crops in the US. Early-season blueberry growers consider flower thrips one of the most important pests. Flower thrips have been shown to reduce the quantity and quality of marketable blueberries. We studied the dispersion of flower thrips for two years in blueberry fields in north-central Florida. A grid of white sticky traps was used to monitor the dispersal and dispersion of flower thrips during the flowering season. To analyze their dispersion, we graphed thrips movement during the season. Based on the data, we visually determined the presence of hot-spots inside blueberry fields. The number of thrips captured on sticky traps inside these hot-spots fit a Gaussian tendency and the respective regression was conducted to describe the curve. To determine the level of aggregation of the thrips population we used Green’s and Standardized Morisita’s indices. Results showed highly aggregated populations of thrips in both years. Formation of hot-spots on blueberry plantings appeared to be random. Results showed that sites where traps captured seven or more thrips per day on days five to seven (after bloom initiation) can become hot-spots. Based on these results, growers will be able to monitor thrips populations, locate and manage hot-spots before they become a problem.

Species 1: Thysanoptera Thripidae Frankliniella (flower thrips)

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