Mapping Azteca barbifex Forel (Hymenoptera: Formicidae) dispersal in georeferenced orange (Citrus sinensis [L.] Osbeck) orchard in the Eastern Amazon, Brazil

Abstract

Damage to orange trees (Citrus sinensis [L.] Osbeck) as a result of Azteca barbifex Forel infestation in orchards of the Eastern Amazon, Brazil, has caused concern among farmers. The presence or absence of A. barbifex ants was sampled in a georeferenced orchard with 4600 plants from June 2007 to June 2008, and the six most representative months of infestation were analyzed. Dispersion patterns of A. barbifex were studied using semivariograms to determine the most suitable spatial distribution model of the species and kriging maps were drawn. Spherical semivariogram models best fit the spatial dispersion patterns of A. barbifex, showing that the patterns of damage resulted from attack foci. The density of A. barbifex nests increased during the dry period, with drastic reduction in the rainy season. The results show that geostatistics is a useful tool for evaluating A. barbifex spatial and temporal distributions and to define reliable sampling plans for use in integrated pest management.