MN Fruit & Vegetable IPM News - Vol. 3, No. 2

Strawberries have started to bloom in most parts of the state. In many fields, the only plants that are blooming are early varieties or the odd plant surrounded by bare soil. When walking your fields, look for holes in the petals of the first flowers that open. If you see flowers with holes in the petals, inspect the nearby flower clusters for clipped buds.

Holes in strawberry petals are usually caused by the strawberry bud weevil or clipper weevil. Clipper weevils feed on the flowers, but the major damage occurs when the female weevils lay their eggs in strawberry buds. After laying the egg, the female girdles the bud, causing the bud to hang down or fall to the ground. During a severe infestation, clipper weevils can remove up to 75% of the flower buds in sections of a field.

Because of the warm April, clipper weevils have become active early this year. We have seen clipped buds in the majority of fields that have started blooming. Normally, clipper damage is confined to small sections of a field, typically near a forest. This year, I am seeing clipped buds evenly distributed across the fields.

To monitor clipper injury, walk the fields. If you see petals with the shot hole appearance over most of a row, you may want to take control measures. Strawberry fields in their first year of production rarely need to be sprayed. Some fields have no clippers on plants of any age. All fields should be monitored. Already this spring, I have seen clipper damage in three fields with no previous history of clipper damage.

Location	Date Sampled	Stage	Strawberry Bud Weevil	Tarnished Plant Bugs
			Clipped Buds/ft	Nymphs/flower cluster	Adults in fields
Faribault	5/17	20% bloom	0	0	0
Alexandria 1	5/17	30% bloom	15	0	2
Alexandria 2	5/15	10% bloom	0.5	0.2 (sprayed)	3
Hugo	5/12	1% bloom	15 (sprayed)	0	0
Aitken	5/15	No bloom	0	0	0

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ACKNOWLEDGEMENTS

Co-Editors: Bill Hutchison (hutch002@umn.edu), Department of Entomology, University of Minnesota, Jeanne Ciborowski, Minnesota Department of Agriculture, Ag. Resources Management and Development Division, and Suzanne Wold-Burkness (woldx018@umn.edu), Department of Entomology, University of Minnesota

The Newsletter is published weekly from May through August, cooperatively, by the Minnesota Department of Agriculture (MDA) and the University of Minnesota (U of MN). Reports are posted on the U of MN and MDA web sites on Fridays. If you have suggestions and/or comments, please send your contributions by 4 p.m., Wednesday to Jean Ciborowski, 651-201-6217, jeanne.ciborowski@state.mn.us, MDA, 625 Robert St. North, St. Paul, MN 55155-2538. You can access the Newsletter at the U of MN web site in htm format at: www.vegedge.umn.edu/MNFruit&VegNews/mnindex.htm and at the MDA web site in pdf format at: http://www.mda.state.mn.us/ipm/ipmnews/

Partial funding for this publication is provided through partnership agreements with the Minnesota Fruit and Vegetable Growers Association (MFVGA) and the United States Department of Agriculture – Risk Management Agency (RMA). These institutions are equal opportunity providers.

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