Area-Wide Survey of Chlorantraniliprole Resistance and Control Failure Likelihood of the Neotropical Coffee Leaf Miner Leucoptera coffeella (Lepidoptera: Lyonetiidae).

The Neotropical coffee leaf miner, Leucoptera coffeella (Guérin-Mèneville & Perrottet, 1842), is a key pest species of unshaded coffee plantations in Neotropical America, particularly in Brazil, where pest management involves intensive insecticide use. As a consequence, problems of resistance to conventional insecticides are frequent, and more recently developed insecticide molecules, such as diamide insecticides, are at risk of becoming ineffective. Thus, a survey of resistance to the diamide insecticide chlorantraniliprole was carried out in high-yield coffee-producing areas in the State of Bahia, Brazil. The likelihood of control failure with this insecticide was also assessed. Spatial dependence among the insect sampling sites was assessed and spatial mapping of chlorantraniliprole resistance and risk of control failure was carried out. The frequency of chlorantraniliprole resistant populations was high (34 out of 40 populations, or 85%), particularly in western Bahia, where 94% of the populations were resistant. Resistance levels ranged from low (<10-fold) to moderate (between 10- and 40-fold) with more serious instances occurring in western Bahia. This results in lower chlorantraniliprole efficacy among these populations, with a higher risk of control failure and exhibiting spatial dependence. These findings invite attention to problems with the intensive use of this relatively recent insecticide and demand management attention, but they suggest that local, farm-based management efforts are likely to be the most effective actions against resistance problems in this pest species.