Interesting farm call this morning. A strawberry grower near Watsonville reported a large group of worms (caterpillars) migrating north out of the mixed cover crop including barley and mustard.
These worms were identified by our new UCCE entomologist Alejandro del Pozo as being a species of armyworm, for which this sort of behavior is not unusual. One distinct characteristic to ID these worms is the ‘Y' shaped suture on their forehead. For instance, the beet armyworm,Spodoptera exigua, could be a problem in strawberries when high infestations are left unmanaged. You could read more about the beet armyworm as pest of strawberries on the UCIPM guidelines at http://ipm.ucanr.edu/PMG/r734300611.html
Knowing that these creatures do feed on strawberries, the advice to the grower is to mow and disk the cover crop to destroy the majority of these worms. Yes, the grower is forfeiting some of the benefit of the cover crop he expected to keep going until the end of August, but the risk to his strawberry crop of this large population of armyworms is greater.
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