Control of the western tarnished plant bug, Lygus hesperus (Knight) in an organic strawberry production system using trap crops, mass-released parasitoids, and tractor-mounted vacuums

Strawberry growers on the Central Coast of California have long observed that the principal cosmetic pest of their crop, the western tarnished plant bug (WTPB) or lygus bug, Lygus hesperus (Knight) establishes populations in strawberry fields in mid-season in relation to the proximity and flowering status of weedy, broadleaved hosts in adjacent areas. WTPB is known to be hosted in winter and early spring by numerous wild hosts which serve as a bridge to the infestation of strawberry fields when strawberry host flowers and small green fruit become abundant. Organic strawberry growers do not use the chemical pesticides registered for conventional lygus bug control nor can they routinely use any organically-compliant materials economically, due to the expense and low efficacy of these products. Instead, organic strawberry growers on the Central Coast rely on field isolation from hosts, adjustment in fresh-market harvest schedules, and whole field deployment of tractor-mounted insect vacuums, or ìbug vacsî. Recently, organic strawberry growers have become interested in experiments with plantings of attractive non-crop vegetation as trap crops which might simultaneously attract WTPB away from strawberry fields (where they can be removed by the use of a bug vac) and increase levels of WTPB-associated predators and parasitoids. This project attempted to gather evidence in support of these trap crop uses in terms of the potential for the release of a massreared a selective WTPB egg parasite, conservation of native natural enemies, and use tractormounted vacuums on the trap crop vegetation for WTPB control in organic strawberry fields