One word any apple producer wants to avoid hearing is “wormy.” But without diligence and action where codling moths are concerned, “wormy” is exactly what you’ll hear. Codling moth larvae can wreak havoc in apple and pear orchards like no other pest, so it’s important to thoroughly scout for them and take immediate action if they are found.
The grey-and-white-striped moths deposit eggs on the underside of leaves, and newly emerged larva immediately seek out the fruit. Though every part of the apple is susceptible to larvae attack, they tend to stick to areas that aren’t easily spotted. They concentrate on the stem end or the calyx end, or they try to drill into an area where two apples touch. Once inside, they munch away at the interior flesh and seeds of the fruit before emerging 3 to 4 weeks later. This is where the most obvious damage occurs, as the exit wounds are often surrounded by piles of caterpillar waste.
Since not a single part of this description is remotely attractive to consumers, it’s easy to see why the codling moth is the primary antagonist of apple growers (and pear and walnut growers, to a lesser extent).
After leaving the apple, the caterpillar finds a protected place to spin a cocoon: beneath loose bark or on the ground under light debris, for example. They overwinter before emerging as adult moths just about the time when trees are in full bloom. Then the cycle begins anew — and if left unchecked, you can see up to four generations in a single season. If conditions are right (warm with moderate humidity), up to 90 percent of the fruit can be infected by a single generation.
Management practices
As with most pests, there are a number of ways you can contain or prevent codling moth infestations. The simplest way to reduce pressure is with physical orchard maintenance. During the growing season and especially after harvest, be sure to clear debris regularly — anything from discarded fruit to piles of leaves can house cocoons. Unnecessary foliage, even trees not being used or maintained, should be cleared.
Scouting is vital. Early in a season, orchards should be scouted multiple times per week. At the first sign of infestation, you should spray, to get ahead of the first generation before devastating damage occurs. If the first-gen moths aren’t contained, the second generation can ruin a crop due to more favorable conditions that breed a more robust pest population. As always, this impact varies by region.
One of the standard insecticides used by apple and pear growers for control of codling moth is ASSAIL® Insecticide. An application of ASSAIL controls first-generation codling moth with the added benefit of secondary pest control as well. Depending on where you grow apples in the United States, ASSAIL will also control aphids, Campylomma, apple maggot, plum curculio and other insects that plague apple crops.
Another option for use early in the season is RIMON® Insecticide. Apply RIMON prior to egg disposition for control of eggs and larvae before they become a problem.
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