Alternative Fumigants to Methyl Bromide for Killing Pupae and Preventing Emergence of Apple Maggot Fly (Diptera: Tephritidae)

Abstract

Abstract Effects of methyl bromide, ECO2FUME (phosphine gas + CO2), Vapam (sodium methyldithiocarbamate), chloropicrin, Telone II (1, 3 dichloropropene), and chloropicrin + Telone II on killing the pupae and preventing adult emergence of apple maggot fly, Rhagoletis pomonella (Walsh), was determined. In an experiment performed inside glass flasks, pupal mortality caused by all fumigants 7 d after a 4-h exposure was significantly higher than in the control, but effects of the five fumigants on pupal mortality 7 d post exposure did not differ consistently even though chloropicrin caused the highest absolute mortality. In contrast, fumigant effects on adult emergence were consistent and clearer in that chloropicrin, Telone II, and chloropicrin + Telone II prevented all emergence of adult flies over 111 - 112 d whereas methyl bromide, ECO2FUME, and Vapam reduced it by only 41 - 73% compared with controls. The differences in pupal mortality and adult emergence patterns suggest that the fumigants acted slowly. ...