Flower Thrips
Frankliniella spp.
Thysanoptera: Thripidae

     In Florida, southern highbush (SHB) blueberries are grown for a highly profitable early season fresh market. Both SHB and rabbiteye (RE) blueberries are grown for commercial sale in Georgia. Flower thrips (Frankliniella spp.) are the key pest of these blueberries. They injure blueberry flowers by feeding and ovipositing in flower tissues, which can lead to scarring of developing fruit. The overall goal of our thrips research is to improve monitoring and management of flower thrips in SHB and RE blueberries in Florida and Georgia.

feeding injury

oviposition injury

Species composition (Arévalo et al. 2009a)

     Our lab developed a key to the most common species found in blueberries in Florida and Georgia. Frankliniella bispinosa (Morgan) is the most common species found in Florida blueberries whereas F. tritici (Fitch) dominates in Georgia.

Dispersal (Arévalo and Liburd 2007b, Rhodes and Liburd in press)

     Flower thrips move into blueberries from other cultivated plants that flower earlier and from wild plant species. They feed and oviposit in all developing blueberry flower tissues. Our plant surveys revealed several reproductive hosts of F. bispinosa in Florida. One of these, white clover (Trifolium repens L.), does not appear to be a source for thrips populations in SHB blueberries in Florida.

Distribution (Arévalo and Liburd 2007a, b, Liburd and Arévalo 2005)

     Flower thrips tend to form ‘hot spots’ in blueberry plantings, which are areas of relatively high population density. These ‘hot spots’ may be related to flower density. The SHB variety ‘Emerald’ often had significantly higher numbers of thrips per trap and per flower than other varieties possibly because it flowers earlier and more uniformly.

thrips hot spots

Montoring (England et al. 2008, Liburd et al. 2009, Liburd and Arévalo 2005, Liburd and Nyoike 2008)

     In blueberries, thrips are monitored using sticky traps or by directly sampling the flowers. Our previous research has shown that white sticky traps are the best to employ. Traps should be hung in or just above the blueberry canopy and spaced at least 94.5 ft (28.8 m) apart to get the most accurate estimate of population size. Our lab developed a “shake and rinse” method that is as accurate as dissecting flowers and much more efficient. Our research revealed a strong correlation between thrips numbers in flower samples and on white sticky traps.
     Economic injury levels (EILs) are an integral part of integrated pest management (IPM) strategies. The EIL is the lowest population density that causes economic loss. We calculated the EILs for ‘Climax’ and ‘Tifblue’ RE blueberries in Georgia, which are approximately 64 thrips per trap for ‘Tifblue’ and 73 for ‘Climax’ when SpinTor® (spinosad) is applied.

thrips monitoring

Control (Arévalo et al. 2009b, Liburd and Arévalo 2005, Liburd and Finn 2003, Liburd and Nyoike 2008)

     Our research has shown that the reduced-risk insecticides SpinTor® (spinosad) and DelegateTM (spinetoram) significantly reduce thrips numbers. The predatory mite Amblyseius swirskii (Athias-Henriot) has shown promise as a biological control agent. In contrast, the minute pirate bug, Orius insidiosus (Say), and predatory mite A. cucumeris (Oudemans) proved ineffective in blueberries.

Current Objectives:

  1. Determine an EIL for flower thrips in southern highbush blueberries in Florida
  2. Determine if controlling flowering weeds will reduce thrips numbers
  3. Test reduced-risk insecticides for flower thrips control

Flower Thrips Publications

  • Arévalo, H.A., A.B. Fraulo, and O.E. Liburd. 2009a. Key to the most common species of thrips found in early-season blueberry fields in Florida and southern Georgia. EDIS-ENY836/IN679. UF/IFAS Extension, University of Florida, Gainesville, FL. http://edis.ifas.ufl.edu/in679.

  • Arévalo, H.A., A.B. Fraulo, and O.E. Liburd. 2009b. Management of flower thrips in blueberries in Florida. Florida Entomologist 92: 14-17.

  • Liburd, O.E., E.M. Sarzynski, H.A. Arévalo, and K. MacKenzie. 2009. Monitoring and emergence of flower thrips species in rabbiteye and southern highbush blueberries. Acta Horticulturae 810: 251-258.

  • England, G.K., E.M Rhodes, O.E. Liburd. 2008. Thrips monitoring in Florida blueberries. EDIS-ENY839/IN692. UF/IFAS Extension, University of Florida, Gainesville, FL. http://edis.ifas.ufl.edu/in692.

  • Liburd, O.E., and T.W. Nyoike. 2008. Monitoring and phenology of thrips in southern highbush blueberries. Proceedings of Florida State Horticulture Society 121: 30-32.

  • Arévalo, H.A., and O.E. Liburd. 2007a. Flower thrips, oviposition and dispersion behavior in early season blueberries. In: D. Ullman, J. Moyer, R. Goldbach, G. Moritz (Eds.). 2007. VIII International Symposium on Thysanoptera and Tospoviruses, September 11-15, 2005. Asilomar, Pacific Grove, CA. 49 pp. Journal of Insect Science 7: 28-30.

  • Arévalo, H.A., and O.E. Liburd. 2007b. Horizontal and vertical distribution of flower thrips in southern highbush and rabbiteye blueberry fields, with notes on a new sampling method for thrips inside the flowers. Journal of Economic Entomology 100: 1622-1632.

  • Liburd, O.E., and H.A. Arévalo. 2005. Integrated strategies for controlling flower thrips in southern highbush blueberries. EDIS-IPM140/IN637. UF/IFAS Extension, University of Florida, Gainesville, FL. http://edis.ifas.ufl.edu/pdffiles/IN/IN63700.pdf.

  • Liburd, O.E. 2003. Cold wintry conditions impacted thrips abundance in Florida blueberries during 2003. May issue, Berry/Vegetable Times 3: 3.

  • Liburd, O.E., and E.M. Finn. 2003. Evaluation of conventional and reduced-risk insecticides for control of flower thrips in blueberries. June-July issue, Berry/Vegetable Times 3: 1-2.

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