Red plastic spheres that mimic apples and catch apple maggot flies on their sticky surfaces. Order these traps in bulk, adhesive sold separately.
For monitoring, use 1-2 traps/acre. Home gardeners, use about 1 trap/100 apples (2-6 traps per tree, one per dwarf tree). Set the traps out 3-4 weeks after petal fall (mid-June). Note: Apple maggots are present but are not yet a significant problem in California. Codling moths are much more common. The damage is easy to distinguish. Apple maggots riddle the fruit, codling moths make an entry and exit hole. See also the Fruit Fly Trap Kit for another apple maggot trap option.
Also available as a kit (PIT601).
The kit contains everything you need to set up 3 complete traps (optional apple scent lure may be purchased separately)