Blueberry bud mite management in Florida with alternatives to endosulfan

     The blueberry bud mite, Acalitus vaccinii (Keifer), is a pest of growing importance in southern highbush blueberry production in the southeastern U.S. It is capable of causing severe yield loss through various degrees of flower bud damage. Blueberry bud mite infestations are challenging to manage for several reasons. Because of their microscopic size of 200 microns and their cryptic lifestyle within the bud, blueberry bud mites are difficult to diagnose by growers who depend on the plant expressing symptoms during winter and early spring months for detection. Severely infested flower buds appear reddened and rosetted. Within the flower buds, blueberry bud mite is out of the reach of most pesticides. Only a limited number of registered chemicals are available. Current recommendations for control of blueberry bud mite rely on pruning infected bushes and post-harvest application of the organochlorine insecticide, endosulfan. However, the Environmental Protection Agency is taking action to end the use of the pesticide in Florida blueberries by 2014, creating a need for alternative control methods for blueberry bud mite.

healthy & reddened infected flowers

pimpled ripe fruit

severe BBM infestation

     In preparation for the phase-out of endosulfan, we have been monitoring the naturally occurring antagonistic fungus Hirsutella thompsonii (Fisher) as a potential biological control agent for suppressing the blueberry bud mite. It can effectively reduce bud mite numbers and often reaches epizootic levels, where the blueberry bud mite infestation of a particular region experiences an epidemic outbreak of the fungal infection.
     Furthermore, tests were conducted to compare the efficacy of Thiodan® (endosulfan) with alternative miticides such as Envidor® (spirodiclofen), and Agri-Mek® (abamectin). Envidor® is a miticide currently labeled on perennial crops such as citrus, grapes, pome and stone fruits, and several tree nuts. However, this product is not yet registered for use in blueberries.
     In our field tests, Envidor® achieved levels of control comparable with those of Thiodan®. The product is a non-systemic foliar acaricide classified as a lipid biosynthesis inhibitor. It has activity on egg, immature, and adult female developmental stages. It takes 7 to 14 days to kill bud mites and will continue killing mites for 50 to 75 days.

Blueberry Bud Mite Publications

  • Weibelzahl, E. and O. E. Liburd. 2010. Blueberry bud mite, Acalitus vaccinii (Keifer) on southern highbush blueberry in Florida. IFAS EDIS Ext. Pub. ENY-858. University of Florida, Gainesville, FL.

  • Weibelzahl, E. and O. E. Liburd. 2009. Epizootic of Acalitus vaccinii (Acari: Eriophyidea) caused by Hirsutella thompsonii on southern highbush blueberry in north-central Florida. Florida Entomologist 92: 689-607.

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