Field control of citrus thrips, Scirtothrips citri, on blueberries with Beauveria bassiana in the San Joaquin Valley of California

Citrus thrips, Scirtothrips citri (Moulton), is a plant-feeding pest most widely recognized for damage caused to citrus and mango fruits. Recently, it has broadened its known host range to become a significant pest of blueberries grown in California’s San Joaquin Valley. Knowledge of this insect’s life cycle coupled with determining that most pupae pupate in the soil in blueberry fields has suggested the possibility of using Beauveria bassiana (Balsamo) to aid in field control of thrips in the upper layers of soil beneath the plant canopy as an alternative to traditional pesticides. Two formulations of B. bassiana (commercially available Mycotrol O versus B. bassiana colonized millet seed) were tested in the field under two different irrigation schemes at two sequential time intervals and data were collected via emergence cages covered with sticky cards. Both fungal treatments were significantly different from the control at time interval one, but not at time two. These results will be discussed further.