Sap Feeding Beetles on Strawberry

May 5, 2012

Sap Feeding Beetles on Strawberry

May 5, 2012

The pictures below are of a species of sap feeding beetles (Family Nitidulidae) found in one section of a local strawberry field.  This case of these insects is pretty interesting simply because they are so uncommon to find in Watsonville.

Conditions of discovery are the following.  The location is a beautiful strawberry field full of big fruit, bordered by apples and blackberries. It is only the five or six rows bordering the apples and blackberries that have these sap beetles.

The beetles occur in groups of four to six mostly on the undersides of the fruit and excavate holes there, in which several beetles at a time gather.  One characteristic of infested fruits is that they are quite mature or even over ripe, which is in keeping with the host and feeding preferences of this family of insects.

As one can see from the first two photos below, distinguishing characteristics of sap beetles are the club shaped antennae, and shortened elytra exposing in this case three abdominal segments.

The solution to this problem is quite simple.  One would want to remove and discard affected fruit from the field, and if very concerned, one could even do a cover spray with an insecticide of the infested rows- it's really not necessary to do the whole field.  Additionally, I have a feeling some of this is related to the moist weather we have had over the past few weeks, so as we move into the drier summer period it's quite probable that these insects will simply go away on their own.

I mention the use of pesticide for management of sap beetles in this article.  Before using these products, check with your local Agricultural Commissioner's Office and consult the product label for current status of product registration, restrictions, and use information.