Spatial and temporal distribution of Opsiphanes invirae (Lepidoptera: Nymphalidae) in oil palm, Pará State, Brazil

Abstract

In this work, we evaluated the spatial and temporal distribution of Opsiphanes invirae larvae (Lepidoptera: Nymphalidae) in oil palm plantations in the state of Pará, where 14 samplings were accomplished from April 2008 to August 2014. The experimental area consisted of 3,582 ha splitted into 89 subareas from 50 to 80 ha each. The spatial distribution was determined by sampling the number of larvae in 10% of the plants (sample unit) in each subarea, in which were obtained the variable value (number of larvae / plant) and coordinates (latitude and longitude). The variability and spatial dependence analysis were made through the incorporation of geostatistical procedures based on spatial modeling techniques by semivariograms. The krigagem maps were generated from the O. invirae larvae’s count data in the field. The O. invirae spatial distribution is aggregated with spatial dependence described by the spherical model, forming patches of 990 to 3700 m (range of the model). Initially, the infestation occurs at the planting edges, with subsequent spread to the entire area. O. invirae larvae disperse by passing from one plant to another, infesting all the area. The results suggest that the traps are placed at the edges of the planting aiming thecollection of adults and, hence, control the population of larvae.