Management of Blueberry Maggot With High Temperatures.

High temperatures were investigated to manage blueberry maggot (Rhagoletis mendax Curran; Diptera: Tephritidae) in field and postharvest situations. To estimate lethal combinations of high temperatures/duration of exposure, blueberry maggot pupae were immersed in water at various temperatures during either 1 or 30 s in the laboratory. Treatments such as 70°C (1 s) or 55°C (30 s) caused 100% mortality of blueberry maggot pupae. In a lowbush blueberry field, soil temperatures at 0, 1, 2, 3, 4, and 5 cm depth were measured with thermocouples following the passage of a flamethrower attached to a tractor in the fall. While the temperatures reached up to ca. 80°C for ca. 1 s at the soil surface, they were <10°C at depths of 3, 4, and 5 cm. In field situations, the energy required to kill all pupae would be expensive to deliver with a flamethrower and this would also cause environmental concerns. An example of application concerning the use of high temperatures in a postharvest situation is discussed, notably immersion of reusable containers in hot water in compliance with Canadian Food Inspection Agency Directive D-02-04 (2015) to prevent dissemination of R. mendax in uninfested areas.