Fruit trees are susceptible to many different kinds of bug or pests. Some are bugs that commonly attack all fruit trees, while others attack only specific types of fruit trees. Fruit tree growers should become familiar with the different bugs that threaten fruit trees, the signs and symptoms of each pest and the different methods used to eradicate them to protect the health of the tree and its fruit.
Kinds of Fruit Tree Bugs
Fruit tree bugs are generally types of worms or caterpillars, moths, beetles or fruit flies. Some attack the tree in the larvae stage, while others are full-grown moths or mature beetles. Additionally, some pests attack the tree by boring into it, others feed on the foliage and still others feed on the fruit of the tree, causing decay and disease. Regardless of the type of fruit tree bug, there are easy ways to identify the bug itself or the signs and symptoms of a bug infestation.
Bugs Common to All Fruit Trees
Some fruit tree bugs attack any type of fruit trees; others are fruit-specific. Common fruit tree bugs that are not fruit-specific are: Japanese beetles, webworms, tent caterpillars, cankerworms, scale, leafrollers, leafhoppers, mites, the oriental fruit moth, fruit flies and the tarnished plant bug.
Specific Fruit Tree Bugs
Some common fruit bugs that are specific to fruit tree type are: the peachtree borer, which primarily targets peach trees; the plum curculio, a snout beetle that attacks plums, cherries and peaches; and codling moths, which are serious pests on apples, but also damage pears, plums and quinces.
Tree-Attacking Fruit Bugs
Some fruit bugs plague only the tree and its leaves and are easily spotted when inspecting the tree.
Japanese beetles, small metallic green beetles with copper-brown wings, can be seen among the foliage of trees. Webworms are caterpillars that build webs of silk around leaves at the end of branches and are easily confused with tent caterpillars, which build webs in the forks of trees. Leafrollers attack the leaves by wrapping leaves around themselves and eating the leaves from the inside out. Scale insects are either armoured or soft and appear as a coloured, raised area on the leaf or stem that is easily removed by a fingernail or knife. Cankerworms, also known as inch worms, can defoliate a tree, killing it quickly by skeletonising the leaves. Oriental fruit moths are borers that push their way into the young limbs and shoots of fruit trees. Finally, mites are small, spider-like bugs that primarily feed on the leaves of fruit trees, turning them brown and destroying vital nutrients.
Fruit tree bugs that attack the fruit directly are fruit flies, the plum curculio and the tarnished plant bug. Fruit flies are one of the most common pests of fruit trees. There are many species of fruit flies, making it a prevalent pest and among the easiest to identify. Most fruit flies are slightly larger than a house fly and have distinctive markings on their wings. They damage fruit by laying eggs in the fruit, which then turn into larvae that feed on the fruit from the inside out, destroying it.
The tarnished plant bug attacks very young fruit, which becomes disfigured and blemished with deep depressions. Similarly, the codling moth severely damages fruit trees when its larvae borrows deep within the fruit, usually apples, and feeds on the seed cavity. Evidence of the presence of the codling moth is a sticky brown substance in the burrowing tunnel.
The plum curculio is a snout beetle that punctures the fruit and then lays eggs, both of which causes damage to the fruit. The plum curculio leaves a small mark in the shape of a "D" on the fruit where it deposited the egg.
Removal methods for fruit tree bugs vary depending on the species of pest. Sometimes, as in the case of codling moth, traps consisting of white, sticky substances that attract the moths are successful at removing the pest from the fruit tree. Other methods for fruit bug removal include manual removal by shaking the tree or picking off insects. Sometimes dummy crops are planted to attract the pest to a host tree. Pheromones, horticultural oils and insecticides are also beneficial ways to eradicate fruit tree bugs.