Apple trees are susceptible to a range of pests and diseases that can damage their leaves. Holes chewed in apple leaves are one of the most common symptoms of these problems. In this comprehensive guide, we’ll cover the various causes of holes in apple leaves, how to identify the culprits, plus effective prevention and treatment strategies.
What Causes Holes in Apple Tree Leaves?
There are several potential reasons you may find unsightly holes chewed in your apple tree’s foliage:
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Insect pests – Caterpillars, beetles, sawflies, and other chewing bugs will feed on apple leaves, removing chunks and leaving behind ragged holes Common culprits are tent caterpillars, codling moth larvae, leafminers, Japanese beetles, and weevils
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Diseases – Certain fungal infections like apple scab, frog eye leaf spot, cedar apple rust, and Alternaria will cause spots with holes on leaves. Bacteria like fire blight also damage foliage.
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Physical injury – Storm damage from hail, high winds, or blowing debris can put small holes in apple leaves. Herbicide damage may also resemble holes
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Wildlife feeding – Deer rabbits woodchucks, voles, and other critters will nip and chew on apple leaves and buds as they browse, leaving holes behind.
Identifying What’s Damaging Your Leaves
To determine what’s munching on your apple tree, closely inspect the damaged leaves and look for any clues:
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Examine leaves for live insects like caterpillars and larvae, especially under the leaf surface. Shake branches over paper to dislodge bugs.
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Note if the holes have smooth, clean-cut edges or ragged, torn edges. Jagged holes indicate insect chewing while clean-cut spots point to disease.
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See if the holes are clustered together or evenly distributed. Grouped damage indicates concentrated feeding by insects versus dispersed spots from disease.
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Consider timing – are new holes actively forming or is the damage static? New holes forming signals an active, current pest issue. Old damage may be from earlier in the season.
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Check if the holes correspond to symptoms of diseases like velvety black undersides, leaf spots, distorted leaf shape, cankers, etc.
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Look for other signs like chewed buds, sticky residue, frass, silk shelters, etc. Check the ground area for animal tracks and scat.
Preventing Holes in Apple Leaves
An ounce of prevention is worth a pound of cure when it comes to pest damage on apple trees. Here are proactive tips to avoid holes in leaves:
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Select resistant apple varieties less prone to insect and disease problems. Liberty, Enterprise, GoldRush and others have increased tolerance.
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Maintain proper tree care through pruning, fertilization, watering, and soil amendments. Healthy, vigorous trees better withstand pests.
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Clean up fallen leaves, fruits, and debris that harbor overwintering insects and disease spores.
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Apply horticultural oil dormant sprays to smother overwintering insects.
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Use pheromone traps and lures to monitor and control pests like codling moth before they damage leaves.
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Encourage beneficial insects by planting pollen and nectar sources. Natural predators prey on pests.
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Consider physical barriers like tree guards, netting, and row covers to exclude insects and wildlife.
Treating Apple Leaf Damage
If preventive measures fail and you spot holes chewed in leaves, take action to control the culprit pest or disease:
For leaf-chewing insects:
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Manually remove insects like tent caterpillars and egg masses. Knock beetles off leaves into containers.
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Apply organic insecticidal soaps, neem oil, or Bt (Bacillus thuringiensis) to target larvae and worms.
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Use pheromone traps and lures to capture and reduce pests like codling moth.
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Attract beneficial insects that prey on pests by providing habitat.
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Exclude pests with row covers, sticky barriers, or trunk wraps.
For diseases:
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Improve airflow by pruning branches to open the canopy and reduce humidity.
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Rake and remove fallen apple leaves which harbor disease spores.
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Apply organic fungicides like sulfur, copper, or Bacillus subtilis as a protective treatment.
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Use antibiotic sprays containing streptomycin to treat fire blight bacteria infections.
For physical damage:
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Provide support poles, windbreaks, tree shelters, or protective netting to protect from weather and debris.
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Install hail protection if recurring hail is an issue in your climate.
For wildlife feeding:
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Wrap tree trunks with hardware cloth or wire guards to prevent browsing.
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Use repellent sprays with bitter tastes applied frequently to discourage feeding.
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Install fencing to physically exclude wildlife from the orchard area.
Common Apple Tree Leaf Pests
Familiarizing yourself with common apple pests will help you identify and control them before extensive leaf damage occurs:
Codling Moth
Codling moth larvae feed on leaves before boring into developing fruit. Look for:
- Ragged holes in leaves, usually near fruits or shoots
- Caterpillars inside bored fruits or shoots
- Cocoons on branches and under loose bark
Tent Caterpillars
Eastern and forest tent caterpillars skeletonize leaves and form silken shelters. Look for:
- Missing entire leaves or branches stripped clean
- Clustered holes along leaf veins
- Silken tents in branch crotches
Leafminers
These tiny flies lay eggs inside of leaves. The larvae mine and feed between leaf surfaces, creating winding trails or blotches.
Japanese Beetles
These metallic green and copper beetles skeletonize leaves between leaf veins, leaving lacy damage behind. Look for:
- Skeletonized patches between veins
- Live beetles on foliage
- Distinctive white grubs in soil
Leafhoppers
Tiny wedge-shaped insects that feed on leaf undersides, causing whitish stippling. Look for:
- Pale stipples or spots on upper leaf surfaces
- Small, triangular bugs on the undersides of leaves
Woolly Apple Aphids
These aphids feed on shoots and limbs, secreting white waxy strands. Look for:
- Fluffy white patches on shoots and branches
- Curled, stunted leaves and shoots
Key Apple Leaf Diseases
Along with insect pests, several important fungal and bacterial diseases will also damage apple foliage. Be on the lookout for these common apple leaf diseases:
Apple Scab
Fungal disease causing olive green spots that turn scaly-black. Severe cases defoliate trees. Look for:
- Dark velvety spots on leaf undersides
- Shriveled, twisted leaves that drop early
Cedar-Apple Rust
Fungal disease requiring juniper hosts. Causes bright yellow/orange leaf spots. Look for:
- Yellow spots on upper leaf surfaces
- Jelly-like tubes on leaf undersides
Fire Blight
Bacterial disease that kills blooms, leaves, shoots, and branches. Look for:
- Rapid leaf wilting and browning
- Shepherd’s crook curling of shoots
- Cankers oozing bacterial ooze
Powdery Mildew
Fungal disease forming white powdery coating on leaves and shoots. Look for:
- White powdery patches on leaves
- Stunted shoot tips
- Premature leaf drop
Alternaria Leaf Spot
Fungus causing small, circular dead spots on leaves that drop out to create holes. Look for:
- Dark spots with tan centers and yellow halos
- Premature leaf drop
When to Call a Professional
For minor damage confined to a few branches, DIY treatment may be sufficient. However, if you see:
- Rapid pest or disease spread
- Large portions of the canopy affected
- Damage recurring year after year
Professional help is advisable. Arborists or horticulturists can provide treatment beyond what home methods can achieve. They have access to more powerful pesticides, fungicides, and tools to effectively protect your apple trees.
Holes chewed in apple leaves are an annoying but common issue that crops up in many orchards. Stay vigilant in monitoring trees and take quick action at the first signs of damage to prevent expanded pest problems. With integrated prevention and control methods, you can outsmart whatever is munching those unsightly holes in your apple tree leaves.
Redhumped Caterpillar Schizura concinna
- Larva will eat entire leaf, leaving only the midvein
- Red head and a wavy black, yellow, and white striped body with a red projection (hump) on the thorax behind the head, 1 1/3 inch long when fully grown
- Occurs in August and September
- More information on Redhumped Caterpillar
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Cankerworms Paleacrita vernata and Alsophila pometaria
- Chews smalls holes between veins at first, later chewing leaf tissue except for major veins, and eventually chewing all of leaves except midvein
- Defoliation typically light to moderate, although it can potentially be severe
- Smooth-bodied, light green to brown, 1 1/3 inch long when fully grown; moves in characteristic looping motion
- Occurs late April/early May until June
- More information on Cankerworms
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Spots on my apple tree leaves
FAQ
Why are there holes in my apple tree leaves?
Caterpillars and worms are often the reason your apple tree leaves may have holes and webbing start appearing. Learn the most common species to expect in our area and how to manage them.
How do I keep bugs from eating my apple tree leaves?
In spring just before new leaves emerge, spray trees with nontoxic horticultural oil. The oil smothers dormant insects and their eggs.
How to fix a hole in an apple tree?
The traditional way to close a harvest hole is to use a small piece of branch, preferably from the tree itself, roughly carve it until it fits the hole and drive it in with a wooden hammer (or a bigger branch). You can cut the branch close to the trunk, but leave a bit of excess, like 0.5 / 1cm.
Why do my apple tree leaves have holes & webbing?
Caterpillars and worms are often the reason your apple tree leaves may have holes and webbing start appearing. Learn the most common species to expect in our area and how to manage them. Eastern tent caterpillars feed on the leaves of apple, crabapple, chokecherry and cherry trees.
What are some common apple tree problems?
While apple trees are notorious for their disease and pest problems, most can be overcome with care and diligence. Familiarize yourself with the common apple tree problems below, and follow these tips to prevent them. Organic apple growers should expect to deal with maggots, worms, beetles, aphids, and more.
Why are the leaves on my apple tree silvery?
Your tree is affected by the disease apple scab. This disease can also attack the fruit (). Question: Why have the leaves on one branch of my tree turned a silvery colour? The most likely cause is a disease called silver leaf, which can also cause branch dieback. Question: The leaves on the young shoots of my apple tree are curled and sticky.
Why are my apple leaves curled & wrinkled?
The apple leaves are curled and distorted with black sticky patches. Apple tree leaves curled and wrinkled from aphid damage. This is classic aphid damage and is typically most noticeable on the underside of apple leaves. Aphids on their own aren’t likely to cause much damage to your apple crop, though you can use insecticidal soap to control them.
Why do plant leaves have holes?
Your plant leaves have holes because some pest is eating the leaves. You need to monitor the plant to check for any insects eating the leaves. The plant leaves can get holes from disease or improper use of chemical sprays on the plant. I’ll give you more details on why there are holes in the plant leaves and how to improve the situation.
Why is my apple tree dying?
If the dieback is accompanied by areas of sunken, dead bark then the likely cause is apple canker. This disease can affect twigs, branches and even the main trunk If the dead branches have numerous pinhead-sized, raised, coral-pink pustules on the surface then coral spot is involved.