Deployment and utility of traps for management of Rhagoletis mendax (Diptera: Tephritidae)

Seasonal captures of adult blueberry maggot, Rhagoletis mendax Curran, on Pherocon AM traps increased l.8-fold when traps were protected from the prevailing winds compared with exposed sites, and l.7-fold when berries were 3 m, based on plots in 11 commercial low bush blueberry fields in New Brunswick and Nova Scotia in 1982. Four-fold more adults were captured when traps were placed in fields containing blueberries than in vegetative fields; captures were 3-fold higher with traps placed in sheltered than exposed locations, and 6-fold higher in weedy than in weed-free locations based on studies in 13 fields in New Brunswick sampled unequally for 6 yr. A logistic curve described cumulative trap captures of adults from 19 fields for 2 yr. The capture rate during the season decreased from New Brunswick to northern Nova Scotia to western Nova Scotia, but the date of 50% capture was similar for all regions. The first adult was caught before the first blue-colored berry was observed in 39 fields over 4 yr. Dimethoate reduced infestation to less than one larva per liter of fruit when applied within 10 d of the first mature female capture. Trap captures of adults within 5 d after a pesticide application reliably predicted continued blueberry maggot pressure in 20 fields with low (0-5) through high (>20) prespray captures monitored for 2 yr.