Moths are a common sight, often fluttering around lights at night, and many wonder if they pose a threat to fruit. While adult moths generally do not consume solid fruit, their offspring, in the larval stage, can be significant pests. Understanding their life cycle and feeding habits provides a more complete picture of their interaction with fruit.
Not All Moths Are Fruit Eaters
Most adult moths do not directly consume fruit in its solid form. Their mouthparts are typically adapted for sipping liquids rather than chewing through flesh. Many adult moths primarily feed on flower nectar, which provides them with sugars for energy, flight, and reproduction. Some species may also consume other liquids like tree sap, honeydew, or juices from rotting fruit.
Some adult moths, particularly those with very short lifespans, do not feed at all. These moths rely solely on energy reserves accumulated during their larval stage to sustain them through their adult life, focusing entirely on reproduction. The presence of adult moths often signals that their larvae might be nearby, or they are seeking a suitable place to lay eggs where the hatched caterpillars will have an ample food source.
The True Fruit Pests: Moth Larvae
Moth larvae, commonly known as caterpillars, are the primary culprits behind fruit damage. These immature stages possess strong mandibles, which are chewing mouthparts designed for consuming solid plant material. Moth larvae feed inside or on the fruit, creating tunnels and leaving behind excrement (frass), which can render the fruit unmarketable or inedible.
The Codling Moth (Cydia pomonella) is a significant pest of apples and pears worldwide. Its larvae typically burrow deep into the fruit, often tunneling to the core to feed on seeds, leaving characteristic holes plugged with frass. This internal feeding can cause the fruit to ripen prematurely and drop from the tree.
The Oriental Fruit Moth (Grapholita molesta) primarily affects stone fruits like peaches, nectarines, plums, and cherries, but can also damage apples and pears. Early generations of its larvae feed on young shoots, causing wilting and dieback, a symptom known as “shoot flagging.” Later generations bore into the fruit, often near the stem end or where fruits touch, creating tunnels that lead to the pit and providing entry points for decay-causing bacteria.
The Plum Moth (Grapholita funebrana) specifically targets plums, damsons, and gages. Its pinkish-white larvae tunnel into the fruit, feeding around the stone and filling the cavity with black frass. Infested plums may show premature bluish discoloration, exude gummy fluid from entry holes, or ripen early and drop from the tree, sometimes leading to significant crop losses.
Protecting Your Fruit from Moth Damage
Safeguarding fruit from moth larvae involves a combination of cultural practices and targeted interventions. Orchard sanitation is a fundamental step; regularly removing and disposing of fallen or infested fruit prevents larvae from completing their life cycle and reduces future populations. This includes picking up fruit from the ground and removing any damaged fruit from the tree.
Pheromone traps offer a way to monitor moth activity and can help reduce populations. These traps release synthetic versions of the female moth’s sex pheromones, attracting and capturing male moths. By trapping males, mating is disrupted, which in turn reduces the number of fertile eggs laid.
Physical barriers can also protect developing fruit. Bagging individual fruits on the tree, often using nylon footies or specialized mesh bags, can prevent larvae from entering once applied. Tree banding, which involves wrapping corrugated cardboard or sticky bands around tree trunks, can trap larvae seeking pupation sites or prevent flightless female moths from climbing the tree to lay eggs.