Attract and kill, an effective technique to manage apple maggot, Rhagoletis pomonella [Diptera : Tephritidae] in high density Quebec apple orchards

"Attract and kill" is an effective technique to control apple maggot (Rhago letis pomonella) in apple orchards. It provided 98.5 to 100% clean fruit at harvest in McIntosh, Liberty, Royal Gala and Jonagold cvs. The traps consi sted of yellow boards (28 cm x 21.5 cm) sandwiched between the two halves o f red spheres (9 cm diam). They were sprayed with 12.5 and 6.3% cypermethri n or 1.3 and 1.7% deltamethrin in de-odorized kerosene, loaded with butyl h exanoate in semi-permeable sachets. The traps were hung on branches 1.20-1. 70 m above the ground. They were placed on the periphery of the plot and po sitioned so as to be visible from outside the tree canopy. The number of tr aps per plot was a function of the length of the plot opposite a possible e ntry site of apple maggot. In columns opposite a forest, entry site of appl e maggot into the plot, the traps in a column were at 2-3 m intervals (0.3- 0.5 traps m(-1)). A trap was also placed on every tree of the first and las t row of a column. The columns were 4-5.5 m apart (0.18-0.25 traps m(-1)). Opposite to prairie grass or a chemically treated plot the traps were m at 2-6 m intervals (0.17-0.5 traps m(-1)) in a column. On the row, the distanc e between adjacent traps was 4 to 12 m (0.08-0.25 traps m(-1)). To achieve commercially acceptable apple maggot control in cvs. McIntosh, Liberty, Gal a and Jonagold apples with "attract and kill" technique, the activity of th e pest should not exceed 13 flies per four traps placed on the periphery of the plot, in other words, 1.6 times the action threshold for the apple mag got in Quebec apple orchards.