The coconut is one of the most important crops in the northeast of Brazil. However, it is affected by several pests. The coconut eriophyid mite Aceria guerreronis, Keifer, (1965), is one of these pests. It is responsible for yield losses. In order to determine the efficiency of Acanat, an experiment was carried out in a field to control the coconut mite. A randomized block design was used, with four treatments (0; 5; 10; 15 ml.L-1) and four replications. The following parameters were evaluated: Damage level, number of living mites and weight of fruits. The smallest concentration of Acanat (5 ml.L-1) reduced the damage caused by mites in 18.9%, the intermediate (10 ml.L-1) in 28.34% and the highest concentration (15 ml.L-1) reduced in 32.43%. Decreasing of living mites in 84.12%, 95.69% and 96.78% was obtained with the same concentrations. The weight of treated coconut fruits with concentrations of 5 ml.L-1, 10 ml.L-1 and 15 ml.L-1 was higher than untreated fruits in 21.87, 43.75 and 65.62%, respectively.
