Mode of dispersal of the sugarcane rust mite (Abacarus sacchari) in the sugarcane field

The sugarcane rust mite (SRM), Abacarus sacchari, infests sugarcane in the Everglades Agricultural Area in southern Florida. Reddish-brown symptoms associated with SRM feeding on leaves appear in April and reach their peak in August-September. Mite dispersal plays an important role in habitat colonization. However, SRM dispersal in sugarcane fields has not yet been explored because of its microscopic size. This study aimed to determine the role of aerial dispersal in the colonization of sugarcane fields. Mite dispersal was studied by measuring aerial mites and mite population on the sugarcane canopy with the elimination of possible ambulatory movement among plants. In addition, the potential dispersal using ambulatory movement as well as precipitation was also investigated. The result suggests that aerial dispersal was the most important method for SRM dispersal. Moreover, females predominated airborne mites, comprising approximately 90% of those measured with 60% gravidity. This strong female bias and its high gravidity in airborne mites further demonstrate the potential role of aerial dispersal in the colonization of sugarcane fields.