Intentional Coverage Gaps Reduce Cost of Mating Disruption for Phyllocnistis citrella (Lepidoptera: Gracillariidae) in Citrus

ABSTRACT The leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is a global pest of citrus and contributes to the incidence and severity of citrus bacterial canker. SPLAT CLM (ISCA Technologies, Riverside, CA) is an emulsified wax that provides sustained release of (Z,Z,E)-7,11,13-hexadecatrienal, the major component of P. citrella sex pheromone. Trials in commercial orchards demonstrated that SPLAT CLM applied to plots of varying width resulted in disruption of trap catch of male P. citrella within treated rows and across untreated rows adjacent to treated rows. SPLAT CLM applied to plots of constant width (10 rows) disrupted trap catch across an untreated gap as the square of the width of the gap. Similarly, the ability of the pheromone source in treated rows to disrupt trap catch across untreated gaps of constant size declined as the square of the width of adjacent treated areas. A coverage pattern of 4 rows skipped for every 10 treated rows resulted in a 4% reduction of trap shu...