Ecology and Aerobiology of Dispersing Citrus Rust Mites (Acari: Eriophyidae) in Central Florida

Abstract

Aerial dispersal of citrus rust mite, Phyllocoptruta oleivora (Ashmead), in central Florida showed a diel periodicity peaking between late morning and early afternoon. The abiotic factors that best described the dispersal pattern were solar radiation, time, and leaf wetness; whereas wind speed, humidity, temperature, and rainfall had minimal effect. The longevity of adult mites removed from fruit was inversely related to constant temperatures between 25 and 35°C. The longevity of mites removed from fruit at 2-h intervals between 0700 and 1300 hours and exposed to ambient temperature and humidity outdoors was inversely related to the time of removal from the host. There was a linear relationship between the number of mites captured in traps and population density on fruit. Mites left fruit harboring extremely low populations and some fruit supporting dense populations yielded hundreds of dispersing mites per day. Mites were readily carried on air currents between adjacent citrus groves. Nearly all of the mites captured in dispersal traps were adult females, and were found in greater proportions in traps than would be expected from the sex ratio of mites on fruit. Studies using isolated fruit in the laboratory showed that a single virgin or inseminated female could initiate a local population through oedipal mating and sibmating. The data are discussed in relation to the selective forces that may shape the dispersal behavior of citrus rust mite and to the potential impact of aerial dispersal on mite management and the development of acaricide resistance.