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Thrips Management in Blueberries Oscar E. Liburd Entomology and Nematology Department University of Florida. Background. Flower thrips, Frankliniella spp. Adults 1/16 of an inch Yellow-orange coloration Wide host range, rapid colonizers Multiple generations per year
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Thrips Management in Blueberries Oscar E. Liburd Entomology and Nematology Department University of Florida
Background Flower thrips, Frankliniella spp. • Adults 1/16 of an inch • Yellow-orange coloration • Wide host range, rapid colonizers • Multiple generations per year • Travel along wind currents
Background - Thrips Lifecycle Pupa non-feeding Larval feeding Male Female
Flower-thrips species 97% 1% Western Florida flower thrips 1% 1% Eastern Other
Goals (2005) • Track the movement of flower thrips into blueberry fields • To correlate thrips population with blueberry flower • development • 3) To evaluate reduced-risk and conventional • insecticides for control of thrips in blueberries
Tracking the movement of flower thrips into blueberry fields • 2 Farms were selected • Each farm had 49 sampling stations (white sticky traps) • Traps were collected every other day for 25 days • Correlated the number of thrips caught on traps with flower development
Relationship between flower development and movement of thrips 40 - 50% 0 - 5% Day 7 Max 25 thrips/trap Day 3 Max 5 thrips/trap
Movement of thrips into blueberry fields 80 – 90% 70 - 80% Day 16 190 thrips/trap Fruit formation Day 21 Day 13 35 thrips/trap 100 thrips/trap
Results Size of thrips populations in relation to flower phenology Percentages of opened flowers 1 10 70 90 20 R = 0.9908; F = 107.8; df = 3,9; P < 0.0001
Questions Q. When do I spray for thrips? Ans. It depends on several factors including history of farm If you have a history of high thrips population you should begin to spray when 5% of the flowers have opened If your farm usually experience low thrips population, you can wait until 50% of the flowers have opened to begin your spraying program Q. What should I spray?
Pesticide efficacy results 2004 2005
Question • What is the relationship between thrips numbers • and injury?
Thrips Injury Hand pollination Thrips release Flower protection Fruit formation counting Flower protection
Thrips Injury fruits 0 thrips /flower
Thrips Injury fruits Oviposition Injury (5 to 10 thrips / flower)
Thrips Injury Fruit dehydration 20 thrips /flower
Thrips Injury Average ±S.E.M.
Thrips Injury oviposition Style Petals • 2 blueberry species in FL • 250 flower per species • 27°C and 80% RH • 15 days Fruits Ovaries
Thrips Injury oviposition a b c c F = 19.16; df = 3,46; P < 0.001
Conclusions • Flower-thrips reduce the quality and quantity of the blueberries • 7 days after bloom the initiation of hot-spots are defined • Thrips are present in blueberry fields for about 25 days from flower opening to ‘petal fall’ • In cases where there are high populations of thrips, insecticides could be more effective if applied when the hot-spots are defined (5-10 days after bloom) • Assail, Diamond and Actara have shown to be significantly more effective than Malathion in • controlling thrips population in blueberry fields
Acknowledgements • Florida Blueberry Growers Association (FBGA) • Michigan Blueberry Growers Association (MBG) • Florida and Georgiablueberry growers • Southern Region EPA grant #: X8-96424405-0 • Small Fruit and Vegetable Lab at UF