Early-season monitoring of leaffooted bug in almond and pistachio produced in California’s San Joaquin and Sacramento Valleys

A complex of large bugs, including three stink bug species, and three leaffooted bug (LFB) species, Leptoglossus clypealis Heidemann, Leptoglossus occidentalis Heidemann, and Leptoglossus zonatus (Dallas), attack almond and pistachio produced in California’s San Joaquin Valley and Sacramento Valley.  For reasons not understood, L. zonatus, has become the predominant LFB species with L. clypealis and L. occidentailis occurring in orchards much less often than in the recent past.   Adult LFB overwinters on e.g. citrus, Cyprus, and pomegranate in aggregations consisting of five to 500 individuals and begin moving into almond in March and subsequently into pistachio during May.  Leaffooted bug can cause substantial economic loss and there is no effective early-season method from detecting their initial arrival into these crops.  We evaluated different colored traps and different plant-based lures including crushed pistachios, pistachio oil, walnut oil, and olive oil as a possible early-season monitoring tool. This paper discusses results from our studies.