Apple growing is notoriously impossible to do naturally. Apple trees are attacked by pests for all varieties of apples, causing the farmer to use both chemical fertilizers and pesticides since they are easy to use.
Worms infesting apple trees are very common, and they can reduce the fruit yield. They are primarily created by the codling moth, which is a warm temperature-producing egg.
During warm weather, the worm infestation can wreak havoc on an apple tree, and the number of worms can be overwhelming at times.
Organically preventing worms on a few apple trees is relatively easy, but it takes some planning and effort.
The most popular and easiest way to grow organic apples without worms is to design a barrier that will protect the apple tree and keep out the worms, such as codling Moths and Apple Maggots.
The barrier can be made from mesh that is impossible for worms.
These barriers can be put on fruit, whole branches, or whole apple trees. It is critical to begin protecting the apples, branches, or whole trees from worm infestations starting late May or early June and through harvest in the fall.
Worms Found in Organic Apples?
The insects that infect apples in the first place are almost certainly codling moth larvae.
Codling moths are the most common insect problem on apples.
The first indication of worm damage is the injury you find in a ripe apple.
- The mother lays her eggs on the
- the young fruit and leaves of apple trees.
- Once the eggs hatch, the young catepillars using it for a food source while on the surface of the fruit and then tunneling inward.
- The caterpillars feed for about three weeks, then tunnel back out of the fruit to find a place to circle a cocoon.
- The larva feeding on the fruit causes it to bruise or rot and eventually drop to the ground.
The worm may no longer be around, but it has left behind a ughly brown mass.
To prevent this invasion, we need to know a bit about the life cycle and behaviors of the worm.
It’s vital to understand the worms life cycle to effectively put early and continuous management tactics into place.
Take away: Non-chemical management measures can work to deter worms from causing damage in many situations and perhaps without pesticides.
How to Control and Prevent Worms
Managing worms can be difficult, especially if you waiting several seasons to start fighting the pest. Once worms get established, it is much easier to maintain them at a low level, than to try to reduce existing worm populations.
If for instance you had an apple tree, and it became established with a high worm population, it may take several seasons before fruit worm damage is lowered to a more acceptable level of 10-20%.
So, in summary, as soon as the season opens, start employing non-chemical management controls.
Sanitation
Sanitation practices start where trash and fallen fruit is removed from the orchard, as this trash can serve as shelter for the codling moth pupa and host larvae.
About six to eight weeks after bloom has passed, you should check the growing fruit for stings, and pick and dispose of, contaminated fruit, particularly in May and June.
You want to do this every one to two weeks to remove any worm damaged fruit.
If the fruit has holes in it, remove it as it has been contaminated with worms. Be sure to put the fruits into a plastic bag and throw them in the trash as composting will not kill any of the caterpillars.
Be sure to pick up apples on a weekly basis, and remember that worms travel very quickly out of the fallen fruit.
Traps
A worm trap is one option for managing apple trees.
These traps put off a smell that will attract moths, which will then become caught in the trap.
Worm traps can be found in most gardening catalogs; it may be fair to say the results are always inconsistent to help decrease the actual number of worms.
To utilize these traps, simply place a couple traps around your yard and one or two on each of your trees. If you place your traps on the apple trees, the moths will come straight for the trees to lay their eggs before getting stuck in the trap.
When you spread them out over your garden, you will be catching the moths before they reach the apple trees.
Traps will do far less damage, while trapping and decreasing the number of egg-laying adults.
Best Results: You should hang the traps in the canopy after the trees have flowered. The rule of thumb is to use two traps per apple tree.
Thinning and Pruning
An upside of thinning fruit in addition to reducing egg-laying sites for worms is that they prefer to burrow into the areas of fruit that is touching something else.
When it is the size of a marble or smaller, remove size 1 or at most one apple from each cluster to enhance larger apple size and provide fewer opportunities to lay eggs.
Prune 15-20% of last year’s growth. Winter pruning takes place when the tree is dormant. Remove dead or diseased branches and pruning promotes airflow/light into the tree canopy, thereby reducing worm population.
Another way to encourage a non-chemical pest management system, prune trees to a height that makes the entire canopy accessible.
Sticky Barrier
To thwart worms from making their way down the trunk, encircle tree trunks with a sticky barrier; this breaks the life cycle by trapping caterpillars as they search for a place to pupate.
Either way, caterpillars that are climbing to the apple trees will become stuck in the sticky material and die.
This will restrict caterpillars from transitioning to other apple trees or climbing back up the tree if they fall off.
Here is the process to follow:
- Use duct tape and a waterproof, sticky material such as Tanglefoot or petroleum jelly to create barrier bands. Tree Tanglefoot is a non-toxic sticky material that will entrap the wingless moths and won’t let them pass while they try to climb up the tree. Wear gloves when applying Tanglefoot as it is very sticky and can be difficult to wash off.
- Wrap duct tape around the tree trunk, shiny side out; pressing firmly into the bark crevices will also prevent caterpillars from slipping under the bands once it has dried. The bands should (of course) wrap all the way around the tree trunk at chest height, approximately four feet above the ground, and be a couple of inches wide.
- The duct-tape layer is needed to protect the bark of the tree from the adhesive sticky substance which has the potential to disfigure or kill the tree if applied without the protective duct tape. Smear the sticky substance down the center of the band. If you use petroleum jelly, make certain there is at least two inches of uncoated band beneath the jelly since it melts and drips downhill.
- Take a regular inventory of the barrier bands to be sure they are not obstructed by other insects or debris or dirt. You will also want to add more sticky substance, especially after heavy rain. The barrier bands can be removed in late July once the caterpillars have entered the pupae stage.
Fruit Bagging
For decades, organic fruit producers around the world have used fruit bagging on trees as a method of fruit protection.
Out of any fruit that producers use bagging on, apples are among the easiest! Bagging the thinned young fruit on the tree will help keep the fruit clean but also successfully protect them from worms.
The concept with fruit bagging is that you can protect developing fruits in a common fruit tree, by placing a physical barrier, like a “bag” of some kind, on the plant to keep common pests like worms from damaging the fruit. Bagging young developing fruit on apple trees can help in the prevention of many fungal diseases as well.
To bag your fruit, you will purchase coverings you can slip over each apple, that grow with the apple as it matures, that have a fine enough mesh to keep worms out. You can also avoid spray insect spraying or application with bagged apples too.
It is a real simple task if you able to do the bagging on a small to medium sized tree that you can do from the ground or on a short ladder.
As for a taller tree, you may only want to bag the easiest to bag apples and just leave the apples that are higher up for the worms.
Selecting Resistant Varieties
If you’re in the process of planting new trees, choose apple varieties that will most likely mitigate potential worm problems down the road.
Early ripening apples, like Jonagolds, Macintoshes, Gravensteins, Red Delicious, and Galas, are less prone to worms compared to late ripening apples.
Good Idea Again! Additionally, you will also want to choose trees that are semi-shallow rootstocks. The shallow rooted trees will make managing worms an easier process.
Beneficial Predators
Nematodes are worm-like parasites that actively search, penetrate, and kill a pest’s pupal stage.
Ladybugs and lacewings will attack the eggs and larvae stage of the creature. Parasitic wasps can certainly attack the worm itself.
Praying mantises can kill the adult moths before they deposit their eggs.
Woodpeckers have been observed eating large amounts of moth larvae.
These birds will prey on the caterpillars when they leave the fruit late in the summer, and in the fall, once larvae cocoon on the tree trunk.
Nuthatches and creepers are worms’ top predators too.
Final Thoughts
Apple trees are more susceptible to pest infestations than any other crop.
If pest management is neglected, the most destructive of these worms can be detrimental to fruit, grower morale, and economically.
To grow organic apples that are worm-free, you should select apple tree varieties that will be more resistant to damage – such as early ripening apples.
Create a consistent practice of cleaning under the apple trees to minimize disease and give those worms no opportunity or place to live.
Do not just store the collected trash near the tree, rather dispose of it entirely.
Removal of fruit and thinning fruit will help limit spreading of the larvae to uninfected fruit.