The most common insect you’ll see on an avocado tree is the ant, which is interesting because ants don’t feed on the avocado tree directly. The ant feeds on honeydew which is secreted by several insects, which makes them both a blessing and a curse. They’re a blessing because seeing ants is an indicator that there is another pest issue. A curse because the ants can often interrupt the biological controls that might otherwise thwart the offending insect. Get rid of ants by first pruning all lower limbs up to a height of no lower than 2 feet from the ground. Then apply a wide band of sticky material around the base of the tree trunk. This will interrupt the ant’s ability to get into the tree allowing you to manage the other pests undeterred.
If you see honeydew on your leaves, especially in combination with a sooty mold, mealybugs may be the cause. Mealybugs are terribly destructive. They suck out the juices of a plant through the leaves, stunting its growth tremendously and even causing the eventual death of the tree in severe cases. Ants are usually present with mealybugs, but once the ants are controlled, natural enemies like birds and ladybird beetles will usually manage the infestation quickly. Minor infestations can be managed by hand picking or dabbing with rubbing alcohol. Bigger infestations can be managed with a strong spray of water and the application of an insecticidal soap or neem oil.
Slugs & Snails
Slugs and snails are annoying in the avocado trees, but the good news is that they only strike when it is cool and damp, usually at night. They attack leaves and fruit. They are easily located and picked off if you are around at the right time, usually after dark and early in the morning. Shallow plates can be placed at the base of the trees and filled with beer. The snails and slugs can’t resist the fermented liquid and will drink themselves to death. If you find your significant other face down underneath the tree, that’s another story.