Oh, the humble apple: a prolific provider in the home orchard. They’re easy to grow and there are a lot of varieties. Unfortunately, along with the tasty fruit, you may end up with a few problems when growing apples, since they’re susceptible to many pests and diseases.
Personally, I don’t aim for blemish-free apples and I’m willing to ignore some cosmetic issues to avoid using chemicals. But you might want picture-perfect fruits. Neither way is right or wrong.
We’re here to help you navigate your way through apple-growing problems, so get comfortable and let’s get going.
1. Rough, Raised Blemishes on the Skin Fruit
You may see small blemishes on the skin that are gold or brown and look like cork. The blemishes are on the surface of the skin only and don’t affect the flesh. This is likely from the apple capsid bug (Plesiocoris rugicollis).
The bug overwinters as eggs. Once the eggs hatch adults appear about two months later. They are green or brown and about a quarter inch long.
When the adults mature and start sucking the sap from the tree, they cause foliage to appear distorted. The larvae generally affect the trees when they target the fruitless.
The corky blemishes don’t harm the apple and you can still eat the fruit, so it’s not one of the worst apple problems.
How to Get Rid of Apple Capsid Bug
Remove dead or diseased vegetation and branches in the winter, and any fallen leaves from the ground around the tree. Encourage birds and hedgehogs to visit your apple orchard or garden. Ground beetles love capsid eggs and bugs (another good reason to be spray-free).
You should also do your best to keep the garden weed free to deny these pests a place to hide.
If all else fails, you can use pyrethrum, but time your spray so that once the apple tree is in flower, you can stop spraying to help the pollinators like honey bees.
2. Black-Edged Hole On The Outside of The Apple
A small hole with black, puckered edges while the rest of the apple looks fine is likely the codling moth (Cydia pomonella). In the caterpillar stage, they will burrow into the core of the apple and fill the tunnel full of froth, which is their excrement.
They leave the fruit to rot when they are done with it. It is unusable and you could lose over 90% of your apple crop. While you can cut the dead part away or feed the apples to your livestock, there probably won’t be any apple pies in your future.
If you cut one of those apples open, you will see a black, messy tunnel from the skin to the core. They live inside the apple for about three weeks, before leaving to pupate or overwinter, depending on the time in the season.
In some areas of the US, this bug is one of the most common apple problems.
How to Get Rid of Codling Moths
Prevention is better than the cure with codling moths. They hide in loose bark, leaves, and weeds around the trees, and any nook and cranny they can find. Remove those as best as you can.
Keep the orchard weed-free, and remove all clutter. Give the tree trunk a light scrub with a stiff brush to remove loose flaps of bark. Be gentle though.
If you see infested apples with frass-filled holes, remove them right away. Remove any dropped fruit, as well.
The best non-chemical control is to bag each fruit individually. That way, the moth can’t get to the apple. This can be time-consuming, but it’s highly effective. Be aware that red varieties won’t develop their full color if they’re bagged, but they still taste good.
Purchase codling moth pheromone traps and hang them in your trees. The male moth is attracted and trapped, reducing its reproduction ability. This won’t eliminate a large infestation, but it does help and it tells you when these moths start hanging out in your orchard.
Place one trap for every three trees within a 50-foot radius. If you get more than 15 moths in a two-week period, use additional methods like trunk banding and spraying an insecticide.
You must apply the insecticide before the larvae dig into the apple because they’ll be protected from any sprays in there. Typically, you’ll want to spray about a month after the blossoms emerge.
CYD-X is highly effective and organic. It should be applied weekly starting a month after blooming. Spinosad is also effective, though it is slightly more damaging to fauna than CYD-X. Still, it’s far better than something like carbaryl, which kills beneficial insects.
3. Ripe Apples Have a Scar Across The Skin
If you see a long, yellowish scar on the skin of the apple, intersected with one or a few blackened holes, you probably have apple sawflies (Hoplocampa testudinea). As the fruit develops, this fly lays eggs that hatch and live in the core of your apple.
In the fall, they tunnel their way out to bore into the soil to overwinter there. You often see a scar at the base of the apple where they come out.
How to Get Rid of Apple Sawflies
If apples fall off the tree prematurely, get rid of them quickly in case they are infected to break the lifecycle. From May to June look for holes. The apples can fall in June, otherwise known as the June drop, when many apple trees self-abort excess apples.
Like coddling moths, it’s a good idea to purchase apple sawfly traps. They are an effective indication of the number of moths visiting your trees so you can get control over this apple problem.
At the same time, purchase grease bands to put on the trunk to prevent insects from climbing up and remove any infected fruits. If the numbers begin to increase in your traps, use a spray that contains pyrethrum.
4. Misshapen Fruit with Insect Holes
This is another insect that gets in early. It is a weevil called plum curculio (Conotrachelus nenuphar). They feed on the flowers, buds, and early set fruit. Adult females lay eggs into fruit that they cut open. The larvae feed on the fruit before leaving when they mature.
The damage isn’t enough to kill the fruit, but the result is deformed apples with ugly blemishes.
How to Get Rid of Plum Curculio
If you have one or two trees, you can go outside, lay paper or a tarp on the ground, and shake the heck out of your trees. The curculio beetles will fall out and you can dispose of them.
You should also make sure to clean up any fallen fruit in the fall and turn the soil under the tree in the spring to expose any larvae. These steps should be enough to deal with this apple problem.
If all else fails, apply a product that contains Beauvaria bassiana or pyrethrin early in the spring and again after flowering.
5. Curled Leaves and Stunted Fruit
If you see fruit with bases that don’t look fully formed, along with curled leaves, you likely have an infestation of rosy apple aphids.
The damage is already done when the aphid feasted on new spring fruit. The best thing to do is spray a good insecticidal soap if you notice an issue.
Check in the curled leaves. You may see the adults clustering there. They are a light purple color and look like they are covered in a thin waxy substance.
How to Get Rid of Rosy Apple Aphids
Rosy apple aphids also spend time on plantain and ribgrass, so eliminate them from the area around your apple trees.
There are many natural predators of rosy apple aphids, so spraying is my last option because it also kills the predators. Ladybugs, lacewings, and soldier beetles all feed on these aphids.
6. Sticky Black Spots on Distorted Leaves
Look at the undersides of the distorted leaves and you will notice the black, sticky spots. This is the classic aphid damage and a common apple growing prolem. You will probably see the aphids in large numbers gathering there as well.
Read our article on aphids, and how to identify and rid your garden of these pests here.
7. White Fluffy Areas on Branches
This is a telltale sign of wooly aphids. They overwinter on one plant and feed on another, like apple trees.
Wooly aphids feed in groups and leave a waxy, wooly mess on branches and stems. These sap-suckers are blue or green and are about a quarter inch long. They look a little fuzzy with a wooly surface.
Common signs include curled leaves, stunted growth, cankers, or galls on the limbs. or yellowing foliage.
How to Get Rid of Wooly Aphids
Wooly aphid infestations aren’t usually severe, but if they are you can spot-treat the worst infected areas on the tree with insecticidal soap and then start regular sprays of organic neem oil.
8. Brown Spot That Starts at The Bottom of The Apple and Grows to Cover It
When this apple problem is present, a small brown spot appears on the bottom of the apple, before growing and affecting the whole fruit. Eventually, any part of the apple with the brown spot starts to decay.
This is called black rot.
The first sign of it can be yellow spots on leaves, called frog eye leaf spots. In severe cases, black rot can affect branches.
How to Get Rid of Black Rot
Remove and dispose of any infected fruit, foliage, and limbs. Prune out any infected parts of the tree as soon as possible.
9. Black Circular Lesions on The Fruit
This is a fungal disease called apple scab. What makes it worse is apple scab creates lesions that may cause black rot.
In early spring, sooty lesions appear on the undersides of leaves. Leaves curl up and fall from the tree. The fruit develops lesions that look like crusty scabs on the skin of the apple.
How to Get Rid of Apple Scab
You can usually just peel the skin and eat the apple as normal. Apple scab is a skin issue only. There are resistant varieties, so ask your local extension office which grow well in your area.
If your apple tree suffers from this one year, remove all fallen leaves and branches. This is a fungal disease that relies on poor orchard or garden hygiene.
10. Dead Patches Around Wounds on the Trunk
Apple canker is a fungal disease and a common apple growing problem. A canker forms in the spring and is likely to kill a branch where it forms. It is a sunken area of dead bark.
Cankers are less likely to form on trees that are healthy.
How to Get Rid of Apple Canker
The best remedy is to prune away any infected branches or areas as soon as possible. It’s more likely in heavy and wet soils.
If the branches are small cut them off completely. For large branches, cut off as much as you can and then seal with a wound paint. Canker thrives on nitrogen and humidity. Make sure to apply any nitrogen heavy fertilizers in spring.
11. Individual Branches Die Back and Turn Black
This is fireblight and is distinctive in that individual branches turn brown or black amongst green ones.
How to Deal With Fireblight
Avoid fertilizers heavy in nitrogen and prune away any infected branches. Cut the branch at least 12 inches from the infection. Burn the branches.
Don’t prune when the tree is in blossom unless you’re cutting infected branches off. Using these steps, you’ll be able to get control over this difficult apple-growing problem. If not, use a copper fungicide.
12. Yellow Spots on Leaves in Early Spring
You will see yellow spots (sometimes amongst cream spots as well) in early spring. By mid-summer, apple mosaic virus will have killed those leaves and the harvest will likely be stunted.
‘Granny Smith’ and ‘Golden Delicious’ apples are particularly susceptible.
How to Deal With Apple Mosaic Virus
Unfortunately, there is nothing you can do and you should remove the trees to prevent spread. You could try pruning away branches with infected leaves, but this won’t kill the disease because it’s systemic.