Management of Western Flower Thrips in SW Florida JOE FUNDERBURK, UNIVERSITY OF FLORIDA CHARLES MELLINGER, GLADES CROP CARE Photo Cheryle O’Donnell

Frankliniella occidentalis western flower thrips Photo Cheryle O’Donnell Established in the southern US (and northern Florida) in the 1980’s Key vector of Tomato spotted wilt virus Very destabilizing to integrated pest management programs including in northern Florida

Tomato spotted wilt virus symptoms on pepper Flecking on pepper due to feeding by Frankliniella occidentalis

Tomato spotted wilt virus Family BUNYAVIRIDAE Genus Tospovirus Species Tomato spotted wilt virus Common name TOMATO SPOTTED WILT (important worldwide species and in Florida) About 1000 plant species are known hosts Seven species of thrips are known vectors

PEPPER Predator-Prey Ratio Management Guides Capacity of minute pirate bugs, Orius insidiosus, to reduce thrips populations Photo Joe Funderburk Predator-Prey Ratio Management Guides 1 predator per about 180 thrips = population suppression 1 predator per 50 thrips = control So if we can alter the predator – prey ratio, we can suppress thrips populations quickly and persistantly

PEPPER Thrips per flower Pirate bugs per flower May & June 1996 Western flower thrips thrips larvae Orius 50 PEPPER 0.8 fenpropathrin 40 30 0.4 20 10 0.0 0.8 12 spinosad per flower Thrips per flower 8 0.4 4 Pirate bugs 0.0 0.8 12 untreated 8 0.4 4 0.0 14 17 19 21 24 28 31 3 May & June 1996 Funderburk, Stavisky &Olson 2000

Thrips/Orius Ratio in Peppers Ratio above this line, spray GCC June 2007

Spinetoram Bioassays of Western Flower Thrips from Palm Beach County, March 2008

Spinetoram Bioassays of Thrips in Pepper Fields IPM field No IPM

INSECTICIDES FOR FRUITING VEGETABLES THAT CONSERVE MINUTE PIRATE BUGS RADIANT thrips and other pests TESORO thrips and other pests REQUIEM thrips, aphids, whiteflies INTREPID lepidoptera AVAUNT lepidoptera Bt’s lepidoptera, coleoptera ECOTROL thrips and other pests

INSECTICIDES KNOWN TO INDUCE WESTERN FLOWER THRIPS IN PEPPER Fenpropathrin Lambda-cyhalothrin Dinotefuran Zeta-cypermethrin & bifenthrin Esfenvalerate Permethrin

RECOMMENDATIONS FOR PEPPER Distinguish between adult and larval thrips and identify adult thrips Economic thresholds: about 10 western flower thrips per flower and about 3 thrips larvae per fruit When peppers are flowering, use insecticides for thrips and other pests that conserve minute pirate bugs Never use insecticides that induce western flower thrips Ultraviolet-reflective mulch Sunflower and other refugia provide a source for minute pirate bugs Vertically integrate management of thrips other pests including pepper weevil and lepidoptera

TOMATO

Dimples on tomato due to oviposition of Frankliniella occidentalis Flecking on tomato due to feeding by Frankliniella occidentalis Ring spots and fruit deformity from tomato spotted wilt infection

Recommendations for western flower thrips in Florida Distinguish between adult and larval thrips and identify adult thrips Economic thresholds: about 1 western flower thrips per flower and about 3 larvae per fruit Alternate between Radiant and other efficacious insecticides Avoid using insecticides that induce western flower thrips populations Ultraviolet-reflective mulch Vertically integrate management program for thrips with management of other pests including whiteflies