common name: blueberry bud mite
scientific name: Acalitus vaccinii (Keifer) (Arachnida: Acari: Eriophyidae)
The blueberry bud mite, Acalitus vaccinii (Keifer), was originally described by H.H. Keifer in
1939 from specimens collected in North Carolina and, at that time, was called Eriophyes
vaccinii Keifer. However, in 1965 when Keifer erected the genus Acalitus, the mite was
transferred to this genus based on its morphological characteristics. This mite has been
reported on both cultivated and wild plants of the genus Vaccinium.
A. vaccinii has been collected in Florida at Melrose and Palatka on commercial stands of
blueberries.
The blueberry bud mite is white, minute and about 200 microns, or 1/125 of an inch, long. The
mite lacks a foretibial seta which puts it in the genus Acalitus. Specifically, it has a shield
pattern with a pair of obscure curved lines toward the rear center between the backward-directed shield setae. The female genital coverflap has longitudinal tubercles.
dorsal-lateral view
ventral view
There is little known on the life history of this mite in Florida. The semitropical conditions in
the state would seem to indicate that the mite does not have an overwintering female as in
North Carolina.
To date this mite has been taken on the commercial varieties of blueberry -- 'Tifblue' and
'Woodard', as well as several new cultivars. Based on typical injury, no variety appears to be
immune to bud mite attack.
It was estimated by one grower in Melrose that over 60% of his crop was lost as a result of
mite and thrips damage. This mite attacks the buds which become closely packed or rosetted on
the stem and then fail to expand and bloom. This results in berry and leaf loss. Keifer stated
that mite feeding caused an unnatural succulence and epidermal roughening or blistering at the
base of the fruit bud scales, causing them to hang in a tight rosette at the base of the fruit stem.
Affected berries appear roughened and malformed. Also, the base of the fruit stem usually is
blistered, retaining the juvenile red color or growing vacciniaceous tissue. In North Carolina,
the rosetting is accompanied by fruit roughening or deformation of the entire cluster, while in
Georgia it is reported not only that fruit clusters are deformed, but that retarded leaf growth
also occurs. In Florida, our observations indicate that bud loss is the prime damage from mite
feeding.
infested and uninfested buds
closeup of damaged and infested buds
Effective control is extremely difficult since the mites are protected by the bud scales. It is
essential that sprays be applied at fairly high pressure (150 to 200 psi) and high gallonage to
obtain effective coverage and penetration. Timing of the application is important but poorly
understood under Florida conditions.
Insect Management Guide for blueberries
- Keifer HH. 1939. Eriophyid Studies V. Bulletin of the California Department of Agriculture 28: 329.
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Keifer HH. 1941. Eriophyid Studies XI. Bulletin of the California Department of Agriculture 30: 192-204.
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Keifer HH. 1965. Eriophyid Studies B-14. California Department of Agriculture, p. 2.
Authors: H.L. Cromroy and L.C. Kuitert, University of Florida
Originally published as DPI Entomology Circular 130.
Photographs: Division of Plant Industry
Project Coordinator: Thomas R. Fasulo, University of Florida
Publication Number: EENY-186
Publication Date: January 2001
Copyright 2001 University of Florida
Featured Creatures
Department of Entomology and Nematology
Division of Plant Industry
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