Mapping the Spatial Distribution of Conotrachelus psidii (Coleoptera: Curculionidae): Factors Associated with the Aggregation of Damage.

Abstract

The guava weevil, Conotrachelus psidii Marshall, is one of the key pest species of Psidium guajava L. fruit in Colombia. Adults that emerge after completing development on the ground attack the guava fruits in some areas of the crop more than in others. During development, the weevil spends 3-6months in the soil, suggesting that edaphoclimatic factors may influence its biology, and hence, the spatial distribution and damage pattern caused by weevils within the guava orchard. Understanding this pattern allows specific control practices to be used at crop sites. The trials were performed in a commercial orchard of 3.5ha. Samples of damaged fruits were taken from each tree, and edaphoclimatic variables such as soil moisture, mechanical resistance, apparent density, texture, precipitation, solar radiation, temperature, and relative humidity were recorded. The data were analyzed using the basic stages of a geostatistical analysis. The findings indicate that the highest numbers of damaged fruits were correlated with areas within the surveyed field where the soil moisture ranged between 27 and 34% in rainy seasons and where the clay content was less than 30% and the silt content was 42% of the surveyed field. A linear model of the infestation was obtained, associated with the climatic variables that determine the environmental conditions and can favor the development of the weevil populations. With the information obtained, localized and efficient management of the guava weevil can be established.