The following tools and techniques are meant to provide some examples of organic pest management (IPM) tactics for apple maggot (scientific name Rhagoletis pomonella) using the “Four T” method.
Our target is the adult apple maggot fly. These are tiny flies that emerge late June through mid July. The idea is to prevent them from reaching the apples they lay their eggs under. Worms in apples are actually maggots that feed on apple pulp.
General calendar time: adult flies emerge late June through mid July
Degree days: first adult emergence occurs around 900 degree days (biofix = January 1)
Tool #1: Apple maggot sticky traps (Type of tool: Mechanical/Monitoring)
The following are three types of traps:
- Actual grocery store bought apples that are coated with Stick-Um liquid adhesive and hung from apple trees.
- Delta traps that are slightly protected from the wind.
- Delta traps plus insect mating pheromone that can be used to attract apple maggot flies to the trap of choice.
Tool #2: Spray kaolin clay (Type of tool: Mineral defensive barrier)
Kaolin clay is a very fine clay dust that, when mixed with water, can be sprayed on apples to provide a fine layer of mineral dust that is not pleasing to poor female flies who only wish to deposit their eggs that turn into hungry, apple-destroying maggots under the surface of the apple skin.
Tool #3: Bag your apples (Type of tool: Material)
Row covers might be expensive and difficult to store for long rows of cabbages, but not for apples. All you need to do for apples is place a plastic (or some other material) bag over them, zip-lock it, and let the poor female apple maggots flies bump their heads against it until they fall to the ground from exhaustion.
Tool #4: Collect your rotten apples in the late summer and fall
In an apple orchard of any size, fallen apples are habitat for apple maggots. Be sure to practice good sanitation and clean up fallen rotten apples so that they don’t have a breeding ground.
Technique for tool #1
You can use sticky traps alone or with insect pheromones.
Technique for tool #2
One application of kaolin clay may be enough to carry you through a whole season. For extremely hot summer weather, you can mitigate heat stress by spraying multiple times. The added coatings of mineral barriers may be hard to scrub off completely at the end of the season, but the reflective properties of the kaolin clay helps bounce light off of the leaves as well as add effectiveness to the defensive properties of the barrier.
Technique for tool #3
Try bagging half of your apples and spraying Pyganic on the rest. The Pyganic will lose effectiveness within a week after it is applied, and overall your apple maggot populations will decrease.
Technique for tool #4:
Pick up the fall apples and burn them or compost them.
For more information
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