Bud mites are very small and usually cannot be seen with the naked eye. Image from Marvin Pritts, Cornell University.

Blueberry bud mite damage to Elliott's blueberry. Photo by Jerry A. Payne, USDA/ARS. www.bugwood.org.

• The blueberry bud mite is can be found in blueberry crops in the eastern United States from Canada to southern Florida and in Texas, as well as among blueberry plantings in the Midwest, including Michigan, Ohio and Indiana.
• Females lay clear, spherical eggs, and multiple generations occur each year.
• Mites can reproduce rapidly, and if populations build to high levels, feeding injury to buds may be seen in spring.

Damage:

• Symptoms are seen in spring as blistering on the outside of bud scales and poor flower set.
• In summer, poor plant growth and fruit set, particularly in the tops of plants, may indicate bud mite infestation.
• Some varieties, particularly Rubel, are sensitive to the mites' feeding; others show few symptoms.

Control:

• Sample current-season growth after harvest. Dissect floral buds nearest to shoot tips and use a microscope to examine for the tiny mites.
• Registered miticide options are limited, but effective registered miticides are available.
• Unless the interior spaces of the bud scales are wetted, it is unlikely good control will be achieved.
• Use of a surfactant to improve the spreading and penetration of the spray is expected to increase control of bud mites.
• Contact your local Cooperative Extension Service office for control measures specifically for your area.

Sources:

Weibelzahl, Elki and Liburd, Oscar. 2010. Blueberry Bud Mite, Acalitus vaccinii (Keifer) on Southern Highbush Blueberry in Florida.

North Carolina State University. 1997. Blueberry Bud Mite. Retrieved 09 June 2011.