Pest Management Options: GF-120 for Western Cherry Fruit Fly
GF-120 should be applied with an ultra low-volume sprayer that will produce large droplets. The droplets do not need to cover the entire tree. A 10 to 15-gallon spray tank with auxiliary sprayer and 12 volt pump can be mounted onto a four-wheeler, and sprayed on at a driving speed of about 6-7 mph.
Swiveling nozzles (to account for different sized trees) are mounted on either side, or a double swivel nozzle body can be used. Because the product is thick and gooey, it should be mixed outside the tank first such as in a five-gallon bucket with an electric drill.
GF-120 is an insecticide that combines the active ingredient, spinosad, with an attractive molasses-like bait. Spinosad is the same ingredient that occurs in Success and Entrust, but in GF-120 it is used at a much lower concentration and different formulation. GF-120 is approved for use in organic production, and can be applied up to the day of harvest. It works by killing the adults upon ingestion, not the larvae within the fruit.
GF-120 won’t provide 100% control if the orchard has heavy outside fruit fly pressure from neighboring farms or backyard trees. Use yellow sticky traps baited with ammonium acetate to monitor for pest population size. One application of imidacloprid (Provado, generics) near harvest may be necessary to kill worms in the fruit for the first 1-2 years of a new GF-120 program.
Advantages of GF-120:
- highly effective after 2 years of use in a widespread area
- applied with a four-wheeler, saving gas and time
- cheaper than many conventional insecticides; the bait costs about $20/acre, including application cost
- safe on natural enemies, groundwater, and has low mammalian toxicity (organic)
- thorough coverage is not necessary
- application time is quick, easy, and only requires minimal personal protective equipment
Disadvantages of GF-120:
- must use at least 2 years (with supplemental sprays) to be effective alone
- must make sure pressure from neighboring orchards is low
- must reapply every 7 days
- must reapply after rain