Pests on Avocado Trees

Whether you are growing avocado trees in your home garden or in a commercial grove, it is crucial to be aware of the potential pests that can invade your trees and damage your crops. Proactive steps to prevent pest infestations along with prompt treatment once trees are attacked may mean the difference between a healthy harvest and a dead avocado tree.

Nipaecoccus nipae, commonly known as the coconut mealybug, feeds on the sap produced by the avocado tree, leaving behind honeydew secretions. The secretions eventually cause mold growth that reduces the plant's photosynthesis and can cause it to lose leaves and even die. Managing infestations is challenging since the bugs produce a protective material which shields it from most insecticides. Control measures include using insecticidal soap during the mealybug's early stages of life, removing affected plant parts and using a strong spray of water to wash the avocado tree.

Selenothrips rubrocinctus, or redbanded thrip, is a pest that originated in the tropics and subtropics. In addition to avocado trees, they also attack cacao, mango, sweetgum and other tropical fruit trees. Redbanded thrips feed on the tree's foliage and fruit, destroying leaf cells, causing leaf distortion and silvering, leaf drop and injury to the fruit itself. Introducing natural predators such as spiders, minute pirate bugs, lacewings and predatory thrips is usually effective in controlling pests.

Fruit flies such as Ceratitis capitata, the Mediterranean fruit fly, and Bactrocera dosalis, or the Oriental fruit fly, both attack and infest avocado trees. These pests cause substantial damage since they feed directly on the flesh of the fruit. According to the University of Florida's IFAS Extension, the Mediterranean fruit fly is one of the most destructive pests in the world. Management measures include trapping fruit flies, spraying trees with naturally derived insecticides, stripping fruit from infected trees and releasing sterile fruit flies into the infested area to reduce the population.

Xylosandrus compactus, the black twig borer, has been found in Florida, Georgia, Texas, South Carolina, North Carolina, Hawaii, Brazil, Indonesia, Cuba, Sri Lanka and Japan. Initial signs of an infestation include twig wilting, visible (but small) entrance holes on the underside of tree branches, cankers, whitish fluid seeping from the tree's wounds, leaf loss and diminished fruit production. Manage infestations by removing and destroying all affected plant materials.

Adoretus sinicus, the Chinese rose beetle, attacks more than 250 different types of plants. The Chinese rose beetle originated in Taiwan and Japan, but can be found throughout Southeast Asia, the Pacific Islands and Hawaii. It is nocturnal, feeding on the foliage of the avocado tree during the night, damaging leaves. Larvae can be found throughout flower beds, cultivated fields and lawns, eating humus rather than live vegetables or foliage. Control measures include introducing the green muscardine fungus to the area to destroy adults and grubs before they are able to do much damage.