Predicting the potential geographical distribution of parasitic natural enemies of the Dubas bug (Ommatissus lybicus de Bergevin) using geographic information systems

Abstract

The Dubas bug (Ommatissus lybicus de Bergevin) is a pest species whose entire lifecycle occurs on date palms, Phoenix dactylifera L, causing serious damage and reducing date palm growth and yield. Pseudoligosita babylonica Viggiani, Aprostocetus nr.Beatus, and Bocchus hyalinus Olmi are very important parasitic natural enemies ofOmmatissus lybicus in northern Oman. In this study, random farms were selected to(a) model the link between occurrences of the Pseudoligosita babylonica, Aprostocetusnr beatus, and Bocchus hyalinus (dependent variables) with environmental, climatological, and Dubas bug infestation levels (the independent variables), and (b) producedistribution and predictive maps of these natural enemies in northern Oman. Themultiple R2 values showed the model explained 63%, 89%, and 94% of the presenceof P. babylonica, A. nr beatus, and Bocchus hyalinus, respectively. However, the distribution of each species appears to be influenced by distinct and geographically associated climatological and environmental factors, as well as habitat characteristics.This study reveals that spatial analysis and modeling can be highly useful for studyingthe distribution, the presence or absence of Dubas bugs, and their natural enemies.It is anticipated to help contribute to the reduction in the extent and costs of aerialand ground insecticidal spraying needed in date palm plantations.