DISCRIMINANT MODELS FOR PREDICTING RISK OF BLUEBERRY MAGGOT (DIPTERA, TEPHRITIDAE) INFESTATIONS IN SOUTHEASTERN NORTH-CAROLINA

Endemic infestations of Rhagoletis mendax are sparsely distributed in North Carolina because not all blueberry Vaccinium spp. fields support these populations. Physical site characteristics of cultivated highbush blueberry fields associated with the presence or absence of blueberry maggot infestations were measured, and discriminant analysis was used to classify the sites. A quadratic discriminant function using 4 variables (bush height, percentage of shade, percentage of soil organic matter, and percentage of sand) provided the best discrimination. A two-variable function using only bush height and percentage of shade proved more economical to use and a chart was developed that allows field determination of the probability of an infestation by blueberry maggots. Altering the crop environment through irrigation may increase the likelihood of an infestation. -from Authors