Managing ambrosia beetles in apple fact sheet
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EmailNew fact sheet on ambrosia beetle management covers black stem borers and maiche borers, two beetles that can become pests of stressed apple trees in Michigan.
Ambrosia beetles are tiny, dark brown opportunistic pests that attack apple trees stressed by one or more causes including cold injury, fire blight infection, flooding and pruning. Female ambrosia beetles bore toothpick-sized holes into trunks to cultivate specialized fungi that become the food for their offspring.
Increased attacks have been noted in the Great Lakes region in the last few years by two species found in Michigan apple orchards:
- Black stem borer (Xylosandrus germanus) females are active mainly in early spring.
- Maiche borer (Anisandrus maiche) females start flying in early to mid-summer.
Michigan State University Extension has developed a comprehensive, four-page fact sheet that describes what we know about their seasonal activity, signs of damage, monitoring methods, and chemical and non-chemical management strategies for protecting vulnerable trees.
