Immunomarking field perimeters to determine Drosophila suzukii movement into red raspberries

Drosophila suzukii Matsumura (Diptera: Drosophilidae) is a serious pest of berry and stone fruits along the west coast. Populations of D. suzukii in early spring are greatest in field perimeters, suggesting that the fly overwinters in these protected habitats.  Current data suggests that the fly may invade berry and stone fruit crops from field perimeters, particularly those containing the noxious weed, Himalayan blackberry (Rubus armeniacus). This study was conducted to determine how field perimeters containing an alternate host (R. armeniacus) and field perimeters containing a non-host (wheat) influence D. suzukii invasion of cultivated red raspberries. In 2011 and 2012 liquid chicken egg whites were sprayed weekly on field perimeters containing R. armeniacus or wheat. Traps placed in the perimeters, at the field-perimeter interface, 30 m, 60 m and 90 m into the raspberries were used to collect flies. All flies were assayed using enzyme-linked immunosorbent assay (ELISA). Higher populations of positively marked D. suzukii were observed in fields near R. armeniacus than fields near wheat suggesting more flies visited or originated from field perimeters with R. armeniacus than with a non-host such as wheat. The implications of managing field perimeters to reduce risk to neighboring crops from D. suzukii populations as an alternative pest management strategy are discussed.

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