Worms In Your Apples?

Introduction

Overview of the Problem

Common concerns about worms in apples often revolve around the damage caused by codling moths and apple maggots, which can infest apple and pear trees, leading to compromised fruit quality. Codling moth larvae, which feed on the developing fruit, can cause significant issues if not addressed promptly.

Effective codling moth control is crucial, as early intervention with codling moth traps, pheromone lures, and sprays, like Bonide orchard spray, can prevent severe infestations. This approach helps protect the fruit from both apple maggot damage and fungal infections.

Addressing these concerns ensures that the apples remain healthy and suitable for consumption, minimizing the risk of damage to your fruit trees and optimizing 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.

Apple maggots are another significant pest, known for infesting fallen fruit and creating feeding holes. Effective management involves using codling moth traps, pheromone lures, and timely sprays to control these insect pests and protect 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, causing damage to the fruit tree before entering the pupal stage, where they transform into adult moths. By late spring and early summer, the cycle repeats as new adult moths emerge, laying eggs and continuing the infestation on apple and pear trees.

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 feed on the surface of the fruit for a few days, then burrow into the center. They feed about three weeks, then 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. These include care of trees and fruit, trapping techniques, and beneficial insects. For best results, use a combination of techniques.

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 crucial for maintaining the health of your apple and pear trees and ensuring high-quality fruit production. 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.

Regular inspection and timely intervention are key to protecting your fruit trees from these damaging pests. For continued success, stay informed and adaptable, utilizing resources and techniques that best fit your garden's needs.

FAQs About Worms In Your Apples

• 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.

• 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, and spraying apple trees with insecticides, like pyrethrin-based sprays. Regular removal of fallen fruit and maintaining garden hygiene, including using beneficial insects and nematodes, can also help manage these pests.

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

  • Begin inspecting your apple or pear tree in early spring, around late March or early April, as the apple tree begins to bud and the trees start flowering. Continue monitoring through petal fall and the growing season, paying close attention during periods of full bloom and fruit development.

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

  • If you find worms in your apples, take action immediately by applying treatments like pyrethrin-based sprays and using codling moth traps. Regular inspections and follow-up sprays, about every two weeks, will help control the infestation and protect your fruit trees from further damage.

References for Further Information

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