How To Monitor For Clipper Weevil In Strawberries

Author:	Pam Fisher - Berry Crop Specialist/OMAF
Creation Date:	October 2002
Last Reviewed:	6 August 2003

In a field 5 acres in size or less:

Check 5 locations near the edge of the field, near sheltered areas, woods or bush.
Mark a 2 ft square.
Check all the buds on all the plants in that section .

There are two ways to evaluate damage:

Count the number of buds which have been clipped. If the average is 13 or more clipped buds per 2 foot square, then control is recommended.
Look at the whole flower cluster, rather than individual buds. Decide if the cluster is highly damaged by clipper or not. A cluster is highly damaged if:
- the primary bud has been clipped
- two or more secondary buds have been clipped
- three or more tertiary buds have been clipped
Use a threshold of 3 or more highly damaged clusters per 2 foot square.

Other monitoring tips:

Holes in petals or base of the bloom indicate clipper weevil adults have been feeding on pollen. Expect to see injury shortly.
Clipper weevil adults are most active when temperatures, especially nighttime temperatures, exceed 16°C.
Clipped buds, which appear brown or dry, have been clipped for a few days or more. Clipped buds, which are green or fresh looking, indicate more recent injury.
Clipped buds often fall to the ground, leaving a stem with a black stubby end. Don't forget to include these in your count.
Clippers do not clip buds in bloom. Monitor twice a week until tertiary buds open.

Figure 1. Monitoring for strawberry clipper weevil in strawberry plants.

Figure 1. Monitoring for strawberry clipper weevil in strawberry plants.