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Friday, April 8, 2011

Strawberry clipper update

I returned to the Lee County farm I visited last Friday to check the sticky traps I placed and count any additional damage.  Also visiting were Seth Holt, Lee County agriculture agent; David Dycus, NCDA & CS regional agronomist; and Brenda Gwynn, new Lee County Horticulture Agent.  The sticky traps I placed at the end of the rows nearest to the woods caught 3 clipper weevil adults, which is a promising result.

Yellow sticky trap placed at the end of a strawberry clipper damaged field in Lee County.  Photo: HJB

Yellow sticky trap with a strawberry clipper weevil (among other insects) in center, circled.  Photo: HJB

Strawberry clipper from sticky trap, up close.  Photo: HJB
 Clippers were also readily distinguished from other weevils on the traps.  If traps can detect strawberry clipper movement from their overwintering sites in the woods into fields, perhaps they can be used to time scouting efforts and insecticides treatments (if necessary).  The four of us also counted damaged plants in the 3 untreated row ends the grower left.  Damage had increased since last week.  Twenty-one of the 31 plants observed had at least one clipped bud, and damage ranged from 1 to 6 clipped buds per plant.  In the treated parts the rows, 11 of 13 plants observed at least one clipped bud.  This suggests that the treatment applied last week is no longer effective and that clippers remain active.  I replaced traps and will be returning next week to check them and assess damage.  My goal is to determine how long the clippers remain active and if the sticky traps continue to catch adults.

Even though flower buds continue to be clipped, I am uncertain that the plants will experience economically significant yield loss from damage at this time of year on young, unopened buds.  Before leaving today, we made plans to conduct an on farm trial at this locations next spring designed to determine if aggressive clipper treatment will significantly improve yield.

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