Insects readily consume fruit, utilizing it as a food source. Their diverse feeding habits lead to various types of damage to fruit crops.
Why Insects Seek Out Fruit
Insects are drawn to fruit for nutritional needs and reproductive strategies. Fruit provides a rich source of energy due to its high sugar content, along with essential vitamins and other nutrients for insect growth and development. For many insects, fruit also serves as a crucial water source, especially in dry environments.
Beyond sustenance, fruit plays a role in insect reproduction. Some species deposit eggs within the fruit, creating a protected nursery and food supply for offspring. Insects employ different feeding mechanisms. Chewing insects, such as beetles and caterpillars, bite and tear fruit, creating holes and tunnels. Piercing-sucking insects like aphids and fruit flies pierce the fruit’s skin to extract internal juices.
Common Fruit-Eating Insects
Many insect species feed on fruit, each with specific preferences. Fruit flies (Drosophila spp.) are common pests that target a wide range of soft, fleshy fruits, including berries, stone fruits, and citrus. Adult female fruit flies lay their eggs just beneath the skin of ripe or ripening fruit, and the subsequent larvae (maggots) feed internally.
Codling moths (Cydia pomonella) are pests of apples and pears, though they can also infest walnuts and quinces. The larvae, or caterpillars, are the damaging stage, boring into the fruit to feed, often near the core. Plum curculio (Conotrachelus nenuphar), a type of weevil, primarily attacks stone fruits like plums, peaches, and cherries, but also apples and pears. Both adult plum curculios and their larvae feed on the fruit, with adults creating distinctive crescent-shaped egg-laying scars.
Japanese beetles (Popillia japonica) feed on a wide variety of fruits, including grapes, raspberries, blueberries, cherries, plums, and peaches. The adult beetles consume the fruit, often preferring thinner-skinned or already damaged specimens. Aphids, small sap-sucking insects, infest many fruit trees such as apples, peaches, and cherries. While they primarily feed on leaves and shoots, heavy infestations can also directly impact fruit quality by deforming them or causing russeting.
How Insects Damage Fruit
Insect feeding causes a range of damage to fruit, affecting its appearance, quality, and marketability. Direct damage includes visible holes, tunneling, and bruising on the fruit’s surface. Larvae of insects like codling moths and fruit flies can tunnel deep inside, rendering the fruit inedible due to internal feeding and the presence of insect waste.
Wounds created by insect feeding also provide entry points for bacteria and fungi, which can lead to spoilage and decay. This secondary damage often makes the fruit unsuitable for consumption. The overall quality of the fruit is reduced, impacting its taste, texture, and market value. Some insects can transmit plant diseases as they feed, acting as vectors for pathogens that further compromise the health of the plant and its fruit. For instance, fruit flies can transfer foodborne pathogens like E. coli and Salmonella to fruit surfaces.