Worms in Apples: Tips for Dealing with a Worm in Apple and Preventing Apple Worms

Combatting Worms in Apples: Solutions for Apple Worms and the Threat of a Worm in Apple

Overview of the Problem

Common concerns about worms in apples often arise due to the damage caused by pests like codling moths, apple maggots, and other insects that infest apple and pear trees. These pests can lead to a compromised fruit quality, with apple worms, such as the larvae of the codling moth, feeding on the developing fruit. If not effectively managed, these worms in apples can cause significant damage to both the fruit and the tree.

Preventing a worm in apple situation is crucial, and controlling codling moths is one of the most effective ways to avoid the infestation of mature larvae. These larvae can further damage the fruit, making it more vulnerable to diseases and infections. Early intervention is key—using codling moth traps, pheromone lures, and sprays like Bonide orchard spray can help kill codling moths before they cause severe infestations. This proactive approach not only protects your apples from apple worms but also reduces the risk of fungal infections and other diseases that may arise as a result of the pest infestation.

By actively managing the worms in apples and ensuring proper treatment to control codling moths, you can maintain the health of your apples. This will ensure that they are suitable for consumption, minimize the risk of damage to your fruit trees, and optimize your overall fruit production.

Purpose of This Guide

The purpose of this guide is to educate you on managing worms in apples and to provide practical solutions for controlling codling moths and apple maggots in apple and pear trees. You will learn how to effectively use codling moth traps, pheromone lures, and sprays like Bonide orchard spray to protect your fruit trees from these insect pests.

The guide covers strategies for detecting moth activity, managing codling moth larvae, and preventing severe infestations, ensuring that your apple trees produce healthy fruit throughout the growing season.

Understanding Apple Pests

Types of Worms and Pests Affecting Apples

Worms in apples, such as codling moths and apple maggots, are common pests that can severely impact apple and pear trees. Codling moths, including both male and female moths, lay eggs on the fruit, and their larvae, or apple worms, feed on the developing fruit, causing damage. The mature larvae then burrow deeper into the fruit, creating tunnels and feeding on the fruit's core.

The apple maggot is another significant pest, known for infesting fallen fruit and creating feeding holes as the larvae feed on the flesh. Effective management involves using codling moth traps, pheromone lures, and timely sprays to control codling moth populations and other pests like the apple maggot, ensuring the health of your fruit trees throughout the growing season.

Life Cycle of Apple Pests

The life cycle of apple pests, such as codling moths and apple maggots, involves four distinct stages: egg, larval, pupal, and adult. In early spring, adult codling moths lay eggs on the fruit or tree flowers, which hatch into codling moth larvae, commonly known as worms in apples. These larvae feed on the developing fruit, often creating a larvae tunnel inside, causing damage to the fruit and leading to infested fruit.

As the larvae feed, they weaken the fruit, which can impact the fruit harvest. The larvae then enter the pupal stage, where they transform into adult moths. By petal fall, the cycle repeats as new adult moths emerge, laying more eggs on the fruit or tree, continuing the infestation.

To control codling moth populations, use pheromone traps to monitor and attract male moths, and apply pesticide sprays to eliminate the larvae and reduce damage. Effective pest management should also account for other insects that may infest the trees and damage the fruit.

Codling Moth Worms in Apples

It is such a satisfying experience to reach up into an apple tree and pluck a shiny apple from a branch. But if you take a big, juicy bite and see that the remaining apple in your hand has brown yuck and half a worm inside -- and you just swallowed -- it may be time to take out the artillery!

The Codling Moth lays its larvae on the developing fruit and leaves of apples and pears, and it can also attack walnuts. When the eggs hatch, the young caterpillars, known as apple worms, feed on the surface of the fruit for a few days, then burrow into the center, leaving behind infested fruit. They feed for about three weeks, during which time they may create visible damage and leave brown heads in the fruit. Afterward, they tunnel out of the fruit and find a place to spin a cocoon.

Biological control has been so successful for codling moth that chemical pesticide use has been greatly reduced. Several effective, non-chemical techniques are available for home gardeners, including the use of horticultural oil, proper care of apple varieties, and trapping techniques. For best results, use a combination of methods to keep your apples safe from pests and maintain healthy, thriving fruit trees.

Identifying Codling Moths

The codling moth is a gray moth 1/2 to 3/4 inch long with mottled gray wings that blend well with most tree bark. The tips of the wings are marked with copper lines and a gold or bronze spot. The larvae are white to light pink "worms" with a dark brown head. Though we all recognize "wormy" apples, the larvae are actually caterpillars. A mature caterpillar is about 3/4 inch long.

Codling moth photo by Scott Bauer, USDA Agricultural Research Service, Bugwood.org

You need to understand their Life Cycle to successfully manage codling moths. They spend the winter as a caterpillar in a cocoon, usually under loose bark on a tree trunk, debris under the tree or in some other protected spot. Adults emerge from the cocoon in April or May. The females lay eggs on leaves and small fruit for about a month. The moths are only active a few hours, before and after sunset, and they mate when the sunset temperatures exceed 62°F. After mating each female deposits 30 to 70 tiny, disc shaped eggs on fruit, nuts, leaves, or spurs. After the eggs hatch, young larvae seek out and bore into developing fruit or nuts. When they reach full maturity they leave the fruit and drop from the trees to search out pupation sites and continue the life cycle in the soil or debris. Some crawl back up the tree to pupate in bark crevices. The rate of development will vary with temperature, proceeding more rapidly in warmer weather and climates. Depending on the climate, codling moths can have two to four generations per year.

Codling Moth Damage

If the codling moth is left uncontrolled, they can cause substantial damage, often infesting 20 to 90% of the fruit, depending on the variety and location. The larvae penetrate into the fruit and tunnel to the core, leaving holes in the fruit that are filled with reddish-brown crumbly droppings called frass.

Identifying Worm in Apple Infestation

Signs of Worms in Apples

Signs of worms in apples include physical damage such as unusual holes and entry wounds on the fruit. You may notice small, dark holes or sticky substances on the surface, which indicate that codling moth larvae (Cydia pomonella) or apple maggots have infested the fruit.

Additionally, the presence of tunnels inside the apple, where larvae feed, can signal a problem with insect pests. If you're finding half of your apples showing signs of infestation, it's bad news and suggests a significant issue.

Early inspection is crucial, especially during the first generation of pests. As the season progresses, be vigilant for signs of the second generation of pests. Detecting and managing infestations early can help protect your apple and pear trees and minimize damage.

How to Inspect Apples for Infestation

To inspect apples for infestation, start with a visual inspection of the fruit on apple and pear trees for signs of worms in apples, such as unusual holes or sticky substances. Look closely for entry points where codling moths or apple maggots might have penetrated the fruit.

After the blossoms have finished flowering, codling moths begin to produce eggs, which can lead to larvae infesting the fruit. Using tools like codling moth traps and pheromone lures can help detect the presence of these insect pests early in the growing season. Additionally, by late June, you should be vigilant for signs of the first generation of pests.

Regularly check fallen fruit, tree flowers, and the soil for signs of larvae and eggs. Implementing appropriate spraying methods, such as using insecticides, can help manage and control infestations effectively.

Management of moths and worms

Codling moths can be very difficult to manage, especially if the population has been allowed to build up over a season or two. It is much easier to keep male moths numbers low from the start than to suppress a well-established population. Begin implementing control measures early in the season.

If a backyard tree or orchard has high moth populations, it may take several seasons of diligently practicing non-chemical control methods, such as using beneficial nematodes and managing developing seeds, to reduce codling moth damage to about 10 to 20% of fruit infested. Implement these methods early in the season and monitor through to early fall. If you have nearby orchards or backyard trees that have no control, this can be a continual source of codling moths.

• Select varieties that are less susceptible to damage, such as early maturing apples and pears.
• Prune trees to a height where the canopy is easy to reach to facilitate non-chemical management of this pest.
• Thinning when fruit is small (the size of a marble or walnut) so that there is only one apple or pear per fruit cluster is a good practice to encourage a larger fruit size and provide less optimal laying sites.
• Be sure to remove any fruit that has small holes made by codling moth caterpillars. Composting doesn't destroy all the caterpillars, so place in a plastic bag and put in your trash. Collect dropped apples weekly because caterpillars move out of the dropped fruit quickly.
• Check fruit on trees for signs of damage every week or two, beginning 6 to 8 weeks after bloom and remove any worm-damaged fruit.

Trapping Moths

Hanging pheromone traps in each susceptible fruit or nut tree can help to reduce codling moth populations but won't completely eliminate damage.  The pheromone lure mimics the scent of a female moth, attracting males to the sticky trap. To use pheromone traps, start in early spring, right at the beginning of bloom. Hang one to four traps per tree (depending on the size of the tree) as high as you can reach.

Check the traps every week or two to remove dead moths and stir the adhesive to maintain its sticky quality. Refresh pheromone lures and change the sticky bottoms every 4 weeks or sooner if they become too dirty to capture moths.

Trunk Banding

Try the Paper Tree Wrap with the Stiky Stuff Sticky Coating. Remove the bands and destroy at the end of codling mating season, end of June or mid-July. Be sure to crush and kill any pupae remaining on the trunk after you remove the band.

To help control the overwintering generation, put new trunk bands up in mid-August and remove and destroy them between November and January. 

Bagging and Maggot Barriers

Excellent control can be achieved by enclosing young fruit in Maggot Barrier bags right on the tree to protect them from the codling moth. This is the only non-chemical control method that is effective enough to be used alone and in higher population situations. However, it is quite time consuming, so this method is most manageable on smaller trees with fewer fruit. You may bag all the fruit on the tree or just as many fruit as you think you will need.

Keep in mind that any un-bagged fruit is likely to serve as a host and increase the pest population so it would be prudent to employ sanitation and mass trapping to keep the population in check. Bagging won't affect the maturity or quality of the fruit, but it will prevent full color development on red varieties. Leave the bags on the tree until harvest. The bags also protect the fruit from sunburn.

To increase the success of this technique check out Surround, derived from kaolin clay. This product label says it forms a hostile barrier to insect pests without affecting fruit growth.

Codling Moth Virus

The codling moth granulovirus, CYD-X offers an effective and selective control of codling moth and is OMRI Listed. The virus is extremely specific to the codling moth and will not effect native pollinators. The virus is available from PVFS and should be applied weekly for best results.

Conclusion

Effectively managing worms in apples is essential for maintaining the health of your apple and pear trees and ensuring high-quality fruit production. Apple worms, such as the larvae of codling moths, are common culprits that cause damage to developing fruit. By understanding the life cycle of pests like codling moths and apple maggots, and employing a combination of prevention and control strategies—such as traps, sprays, and physical barriers—you can significantly reduce infestations and prevent a worm in apple problem.

Regular inspection and timely intervention are crucial in protecting your fruit trees from these damaging pests. By actively monitoring for worms in apples and taking action early, you can minimize the impact on your harvest. For continued success, stay informed and adaptable, utilizing resources and techniques tailored to your garden’s specific needs to prevent apple worms from affecting your crops.

If you're looking to plant new trees, check out our apple trees for sale and find the perfect variety for your orchard.

FAQs About Worms in Apples: Tips for Dealing with a Worm in Apple and Preventing Apple Worms

• What causes worms in apples?

  • Worms in apples are typically caused by pests like codling moths and apple maggots. These insects lay their eggs on the apple or pear tree, and when the eggs hatch, the larvae, or apple worms, feed on the fruit, leading to visible damage. The larvae often burrow into the fruit, leaving behind brown heads and other telltale signs of codling moth damage.

• How can I prevent worm infestations in my apple trees?

  • Preventing worm infestations involves strategies such as hanging codling moth traps to monitor and control codling moth populations. You can also use pesticides like pyrethrin-based sprays. Regular removal of fallen fruit, monitoring for signs of damage, and maintaining good garden hygiene can help. Additionally, introducing beneficial insects and using techniques like corrugated cardboard traps or applying horticultural oil are effective ways to manage pests organically.

• When should I start inspecting my apple trees for worms?

  • Start inspecting your apple or pear trees in early spring, around late March or early April, as the trees begin to bud and the first apple blossoms appear. Continue monitoring throughout the growing season, paying close attention during petal fall and periods of full bloom. Be vigilant through the development of the fruit and into early September, when the second generation of pests may emerge.

• What should I do if I find worms in my apples?

  • If you find worms in your apples, act immediately by applying treatments like pyrethrin-based sprays and using codling moth traps. Regular inspections and follow-up spray applications, about every two weeks, will help control codling moth infestations and protect your fruit trees from further damage. Remove infested fruit to prevent larvae from completing their cycle and pupating in the ground or nearby storage areas.

• How can I manage a codling moth infestation?

  • Managing a codling moth infestation requires a multi-faceted approach. Start early in the season by placing pheromone traps to capture male moths and reduce the population. Regularly inspect the fruit, especially after full bloom and as the fruit begins to develop. Remove damaged fruit, use organic control methods like kaolin clay to deter feeding, and if necessary, apply pesticides to control infestations.

• How many generations of codling moths are there in a season?

  • Codling moths can have two generations per growing season. The first generation emerges in spring after adult moths emerge from their winter cocoons. The second generation typically appears in late summer, usually around early September, continuing the infestation cycle. Regular management of codling moths throughout both generations is essential for preventing significant damage.

• What should I do with infested fruit?

  • If you discover infested fruit, remove it immediately from the tree and ground to prevent further larvae development. Composting may not eliminate the pests, so place infested fruit in a sealed plastic bag and discard it. This helps prevent larvae from emerging and eating your fruit or pupating in the soil.

• Are there any natural ways to control codling moths?

  • Yes, there are natural methods to control codling moths, such as introducing beneficial insects that prey on the moth larvae. You can also use pheromone traps to capture and reduce male moths, and apply organic products like horticultural oil or kaolin clay to deter moths and larvae from feeding on your fruit.

• Can I prevent codling moths with just traps?

  • While pheromone traps are useful for monitoring and reducing male moths, they are not a complete solution. To prevent significant damage, you should also use sprays, remove infested fruit, and consider physical barriers like corrugated cardboard or hanging bags to protect the apples.

• Do codling moths affect all apple varieties equally?

  • Some apple varieties are more susceptible to codling moth damage than others. Varieties with thicker skins or those that mature earlier in the season may be less prone to infested fruit. Choosing apple varieties with natural resistance to pests can help reduce the need for pest control methods.

• Can other insects harm my apple trees?

  • Yes, apple maggots, bees, and even birds can also impact apple trees. However, codling moths are among the most damaging pests. It is important to use integrated pest management strategies that include monitoring for these other insects as well, to ensure healthy, productive fruit harvests.

References for Further Information

• Integrated Pest Management, UC Davis: Codling Moth
• Michigan State University Extension: Organic Management of Codling Moth