Like any fruit tree, apple trees should be treated with a pesticide to prevent insect infestation. Apple trees are particularly susceptible to apple maggots, codling moths and weevils, but can also attract more well-known pests such as ants, aphids, beetles, grasshoppers and slugs. Organic pesticides are readily available, though alcohol spray should not be used on apple trees.
Considered an all-purpose organic pesticide, Garlic Barrier will keep most pests from an apple tree, including codling moths, apple maggots, ants, aphids, grasshoppers and slugs. Garlic Barrier is available in a liquid concentrate, which is then diluted with water and sprayed on to the tree. The pesticide is absorbed into the tree roots, limbs and greenery. According to extremelygree.com, the product does not alter the taste of tree fruits and the strong garlic smell dissipates quickly.
Surround W.P. Kaolin Clay
A naturally occurring mineral that can be applied directly to fruits on the tree, Surround W.P. Kaolin Clay repels many common apple tree pests, including codling moth, apple maggot, ants and aphids. The clay is mixed with water and sprayed onto the fruit, where it becomes a white film that sticks to insects and encourages them to move on. The spray can be applied throughout the growing process, up to the date of harvest. The clay mixture can be rubbed off.
Sharp Shooter Insecticide
A general, all-purpose insecticide that is made from lemon juice extract, Sharp Shooter Insecticide may be sprayed on apple trees when insects first appear. This product is effective against ants, aphids, beetles and slugs. Sharp Shooter Insecticide is available as a liquid that can be diluted with water and sprayed onto the foliage of the tree as often as needed until pests disappear.
Nematodes, which are small ringworms, are the most effective treatment for weevils. Sold as a pesticide that must be applied in overcast conditions, these small insects are available in packets that may be mixed with water and applied directly to the tree. The nematodes prefer wet conditions and sun will neutralize their effectiveness. After application, the nematodes will sit on their tails awaiting their prey, which includes weevils and gnats.