Thrips Management in Blueberries Oscar E. Liburd Entomology and Nematology Department University of Florida

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

Background - Thrips Lifecycle Male Female Pupa non-feeding Larval feeding

Flower-thrips species Florida flower thrips Western Eastern Other 97% 1%

Goals (2005) 1)Track the movement of flower thrips into blueberry fields 2) 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

Day 3 Max 5 thrips/trap 0 - 5% % Day 7 Max 25 thrips/trap Relationship between flower development and movement of thrips

Movement of thrips into blueberry fields Day 21 Day 13 Day % 80 – 90% Fruit formation 100 thrips/trap 190 thrips/trap 35 thrips/trap

Results R = ; F = 107.8; df = 3,9; P < Size of thrips populations in relation to flower phenology Percentages of opened flowers

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

Effect of SpinTor on thrips population over 48 hours

Question Q.What is the relationship between thrips numbers and injury?

Thrips Injury Flower protection Hand pollination Thrips release Flower protection Fruit formation counting

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 2 blueberry species in FL 250 flower per species 27°C and 80% RH 15 days Style Fruits Petals 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 Georgia b lueberry growers Southern Region EPA grant #: X Small Fruit and Vegetable Lab at UF