Apple maggots or codling moth caterpillars make up most of the worms you see in apples. The larvae eat into the apple, then tunnel to the apple core. Holes in the apples filled with reddish-brown droppings, or frass, let you know your apples may be infested with larvae. You can get rid of apple tree worms using natural, safe methods. As a home gardener, you have access to only a few insecticides considered safe enough to manage the problem.
Apple tree care
Plant apple tree varieties with apples that mature early. This helps reduce the possibility of larvae infestation.
Prune your apple trees so you can reach the upper branches of the trees and remove codling moth cocoons.
Check the apples on your trees every week or every two weeks for damage. Start checking six to eight weeks after your apple trees bloom. If you find any apples with larvae, or see the holes filled with frass, remove them immediately and discard the apples. This reduces the larvae population on your apple trees and helps the remaining apples grow bigger. Remove and throw out all infested apples you see dropped on the ground.
Hang codling moth traps on your apple trees, as high as you can in the upper tree branches.
Use one to two traps per small tree and two to four traps per large apple tree. The traps consist of a pheromone or sex attractant and a sticky bottom. Male codling moths fly into the traps expecting to find female moths. Trapping the males means cutting down on mating, which reduces the amount of laid eggs.
Check the moth traps weekly to remove the dead moths.
Thin your apples until you have one apple per cluster.
Cut a 5 cm (2 inch) slit on each bag's bottom fold.
Slip any apple that is 1.25 to 2.5 cm (1/2 to 1 inch) in diameter through a bag's slit. The slit creates a seal around the stem. Staple the bag opening closed. Although time consuming, this method works well, including in high codling moth populations.
Bag as many apples as you plan to use or bag all the apples. You will get larger apples from the thinning plus you protect your apples from sunburn.
Open the bags around harvest time to check for ripeness, then restaple them if the apples are not ready.
Perform two to three sprays of specialist codling moth biological insecticide, every 10 to 14 days in the spring, during the first generation of codling moths. Spray again when the eggs begin to hatch.
Spray once during the summer, at the start of every new egg hatch. Spray again about 14 days later for high codling moth populations.
Spray no more than six times during a season and not within seven days of apple harvest. You can use the treatment safely around your family and pets.
You can buy specialist insecticides and other supplies at garden centres.