Brown apple tree leaves

APPLE TREE PESTS AND DISEASES

This page with picture and clear descriptions will help you identify the common pests and diseases although if you want advice on how to prevent them in the first place then the page here has more specific information on preventative measures.

The article below lists pests and diseases which affect the leaves, branches, fruit, blossom and the roots.

PEST AND DISEASES AFFECTING APPLE TREE LEAVES

CURLED AND DISTORTED LEAVES, BLACK STICKY PATCHES ON LEAVES

Adult aphids on a leaf

SOME LEAVES COVERED IN WHITE POWDER

Infected leaves may be slightly smaller than normal and may be distorted. It can spread to fruit and even twigs and branches. It first becomes noticeable when young leaves emerge in spring.

Leaves affected by Powdery Mildew

YELLOW / OLIVE AREAS ON LEAVES

Leaf affected by Apple Scab

SMALL GREEN CATERPILLARS ON LEAVES, LEAVES AND BUDS DAMAGED

Winter Moth Caterpillar hanging by a thread

PEST AND DISEASES AFFECTING APPLE TREE BRANCHES AND TRUNK

BARK CRACKED, PATCHES OF BARK SUNKEN DOWN

BRANCHES HAVE IRREGULAR LUMPS ON THEM

The only permanent solution is to destroy the tree. The bacteria will remain in the soil for two three more years.

Apple tree stem affected by Galls

BRANCHES HAVE ELONGATED WHITE FLUFFY AREAS ON THEM

Apple tree stem affected by Woolly Aphid

PEST AND DISEASES AFFECTING APPLE TREE FRUIT

INSIDE OF THE APPLES HAS A BROWN TUNNEL IN IT

There will be a tunnel in the fruit of varying length which is brown in appearance and filled with excrement from the caterpillar. This damage has been caused by the caterpillar stage of the Codling Moth. Click here for our detailed page on identifying and treating this pest.

Apple affected by Codling Moth

SKIN HAS BROWN, PIN HEAD SIZED MARKS. FRUIT TASTES BITTER

Apple affected by Bitter Pit

SKIN HAS BROWN RASED OR SUNKEN AREAS

Apple affected by Scab

BLOSSOM WILT

Blossom Wilt affects fruit trees including apples, pears, plums and cherries. It is a fungal disease (Monilinia laxa and Monilinia fructigena) which has the following symptoms:

• Blossoms wilt then shrivel up and become dried out.
• Leaves near the blossoms (on the fruiting spurs) also turn brown and shrivel up.

If conditions are damp, the affected leaves will have small, light brown, fungal raised areas on them.

If any fruit manages to survive it will turn brown and rot.

Damage by Blossom Wilt

There are no chemical controls available to UK gardeners to control this fungal infection.

Non-chemical control is based on pruning off any damaged blossoms including the fruiting spur they are on. Burn them, do not put them on the compost heap. Do the same with any fallen leaves. The idea is to minimise the spread of the spores and hopefully prevent them over-wintering and re-infecting the tree the next year.

EUROPEAN RED MITE

The red eggs are from the European Red Mite. Because I have never encountered them personally I can’t really offer advice as to how to control them. However I do know that they are eggs which will hatch out in spring and become tiny red mites.

These will damage the leaves of your apple tree. I would certainly scrape the eggs off immediately before they hatch and take a close look around the tree for more of them. When the eggs hatch they loose their colour so this will give you an idea of the scale of the problem this year.

To the best of my knowledge the European Red Mite is not connected with the more common Red Spider Mite. More information can be found on the link here.

COMMENTS / QUESTIONS LEFT BY OUR READERS

We have moved the Apple Tree pests and diseases comments and questions section to its own page which can be visited by clicking here. On that page you can view all the previously asked questions / answers / comments and also ask any new questions of your own.

The questions and answers page contains a large amount of additional information about apple tree problems.

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Why Apple Trees Drop Leaves Early (and How To Fix It)

I just got my Fuji apple tree and it has a couple of leaves that are yellowing, browning, and falling off. I’m aware that apple trees are deciduous and normally lose their leaves in the autumn, but the only problem is that it’s still summer! I wanted to find out why apple trees drop their leaves early and how to fix it, so I did some research. Here’s what I found.

Apple trees commonly drop their leaves early due to a change in watering, weather, or nutrients. Additionally, transplant shock and diseases such as apple scab, cedar apple rust, and fire blight can cause apple trees to lose their leaves in the summer. After resolving the issue, the tree should regrow its leaves.

So, while apple trees can lose their leaves early for several reasons, how can you identify which issue is causing it, and how can we fix it?

By the way, if you’d like some gardening supplies that are on sale this fall and winter, check out these new items on Amazon.

Over or Under-Watering

If an apple tree is over-watered, its roots will start to drown. This creates stress and the tree will soon drop its leaves. On the other hand, under-watering causes the leaves to curl to conserve moisture. If not addressed, the leaves will continue to dry and eventually—turn brown and fall off.

Over and under-watering are one of the most common reasons why apple trees lose their leaves early. It’s also really easy to do, especially if the soil isn’t well-draining. Fortunately, a few tips can help make sure this never happens again.

How to Fix

The best way to water your apple tree is to first check the soil’s dryness. You can do this by pushing a finger into the soil, up to the second knuckle. The goal is to only water when the soil is dry. Additionally, apply 1-2 inches of both compost and mulch to help the soil retain water and reduce evaporation.

Compost is not only a great way to provide nutrients to apple trees (often replacing fertilizer), but it also improves the richness of the soil. With each 1% increase in the soil’s richness, it can hold an additional 20,000 gallons per acre.

Applying 1-2 inches of compost every 1-2 months will be sufficient for your apple trees. You can apply it directly on top of the soil, just make sure to keep it at least 3 inches away from the tree’s trunk.

Mulching is another essential practice for apple trees. The mulch shields the soil from baking in the sun or drying in the wind. In short—it greatly reduces soil erosion and evaporation.

Since the soil retains more water and isn’t oxidized from the sunlight, its beneficial bacteria can thrive. This bacteria in turn provides nutrients for the apple tree (nutrients that are normally found deeper in the soil). In return, the apple tree’s roots provide sugar (from photosynthesis) to the soil bacteria.

You can apply 1-2 inches of mulch such as leaves, bark, pine needles, or straw to the base of apple trees. Reapply the mulch every 3-6 months. Like compost, keep the mulch at least 3 inches away from the tree’s trunk.

So, by only watering your apple tree when the soil is dry, and by using compost and mulch, your apple tree will be more self-sufficient and have much less of a chance of developing early leaf loss from water stress.

If your apple tree’s soil is currently waterlogged, which is common in heavy clay soils, you’ll need to amend it first before watering it again. You can improve the soil’s drainage by adding sand or perlite, or as a worst case, relocate or repot the tree with fresh soil.

Extreme Weather

Generally, apple trees can handle temperatures between -25ºF and 100ºF but can get stressed when there’s an early frost, extreme heat, or a swing in weather. This stress causes early shedding of the tree’s leaves, blossoms, and fruit. To prevent this, monitor swings in weather and protect the tree if possible.

While most apple trees do best in USDA hardiness zones 5-8, swings in temperature can still be harmful. Quick swings in temperatures of 30ºF or more can stress the tree, leading to leaf, blossom, and fruit drop.

How to Fix

Aside from checking the weather, here’s what we can do to protect apple trees from harsh weather:

Potted apple trees can simply be brought indoors during extreme weather, while planted apple trees will need to be shaded from the heat or insulated from the cold with sheets or cardboard.

Additionally, you can position apple trees to face a southern direction to get the maximum amount of sunlight and warmth. Planting next to a southern-facing wall will work as well, with the wall reflecting sunlight and heat onto the tree into the night. This is especially helpful if you live in a colder region.

On the other hand, if you live in a hotter region, consider taking a permaculture approach and creating shade from taller, more heat-tolerant trees. Also, mulch is a must-have for all apple trees, especially those in hotter regions. This will drastically cool the soil and roots, which helps cool the rest of the tree.

While many of us check the weather daily, sometimes it can change on a whim. Fortunately, there are some apps you can use on your smart devices to help alert you when there is extreme weather such as frost, as well as a flash flood, tornado, and more.

However, if your apple tree is getting the proper amount of water, and isn’t getting an early frost or extreme heat, nutrition would be the next thing to check.

A Lack of Nutrients

An over or under-abundance of nutrients can cause apple tree leaves to drop early. Without the proper nutrients, apple trees will become stressed and begin to shed their leaves. For best results, use fertilizer once or twice per year or 1-2 inches of compost every 1-2 months during the growing season.

While too many nutrients can overload the tree and lead to leaf drop, too few nutrients can mean the tree will have a hard time supporting its leaves. In times of stress, apple trees tend to shed their less vital parts first, such as their leaves, blossoms, and fruits.

How to Fix

Providing your apple tree with a quality fertilizer at regular intervals will help ensure it has the proper nutrients to thrive, which can prevent early leaf drop.

Chemical fertilizers are typically more potent than natural fertilizers, and therefore only need to be used 1-2 times a year. Mature apple trees normally like fertilizer with a balanced NPK (such as a 5-5-5), while younger apple trees prefer one with slightly higher nitrogen. A good fertilizer to use for apple trees is Down to Earth’s Fruit Tree Mix, which can be found on Amazon.

On the other hand, compost is a more natural fertilizer and breaks down in the soil easier. Because of this, it should be applied every 1-2 months. The nutrients in the compost are also more usable by the tree than most chemical fertilizers and benefit the soil life, which then promotes the apple tree’s health.

If you’d like to take it a step further, you can even make your own apple tree fertilizer at home. For more about how to do this, you can check out my recent post: Create an Amazing Homemade Fertilizer for Your Fruit Trees.

Whichever method you choose, remember that soil pH is equally as important (if not more than nutrients). After all, if the apple tree’s soil is too acidic or alkaline, the roots won’t be able to absorb nutrients properly from the soil.

Apple trees prefer a soil pH of 5.8-7.0. You can check your apple tree’s soil pH by using pH strips or a pH meter. I personally prefer pH meters since they’re affordable and easy to use. Simply stick into the soil and you’ll have your reading (no batteries needed!). To see which pH meter I use, check out my recommended tools page.

Transplant Shock

Transplant shock can create excess stress for apple trees and lead to their leaves curling and dropping early. Generally, transplant shock occurs when apple trees go through a stressful relocation or repotting. Transplant shock’s effects can be reduced by doing a swift transplant and preventing damage to the rootball.

If you’ve recently relocated or repotted your apple tree, its early leaf loss could likely be caused by transplant shock.

Sometimes, you just need to move your apple tree. For example, you might find that a different part of your land suits them better. Or maybe you have a potted apple tree that has poor soil drainage and needs to be repotted with fresh soil.

In either case, transplant shock can be one of the most stressful events for apple trees, depending on their current state of health and how intrusive the transplant is.

I’ve transplanted many fruit trees and have recently repotted my Fuji apple tree. Because of this, I feel like I have this process down pretty well.

How to Fix

Here are some steps that I use to prevent transplant shock with my fruit trees:

1. Have the new ground (or pot) prepared
2. Remove as much of the tree’s current topsoil as possible, without damaging the shallow roots
3. Grab the base of the tree’s trunk and wiggle lightly
4. Using your other hand, scoop up and support the rootball
5. Lightly place the tree in the new ground (or pot) and fill it in
6. Make sure the soil is at the same level on the trunk as before
7. Apply 1-2 inches of compost and mulch to the top of the soil
8. Water generously and add more soil as needed

After performing these steps for my transplanted Fuji apple tree, it had little stress and its leaves started perking back up almost immediately.

Keep in mind that it’s difficult to prevent all of the stress from transplanting and sometimes the tree just won’t react well. It can take up to one year for an apple tree to recover from transplant shock and establish a new root system.

Just do your best and the tree will hopefully recover soon!

Diseases

Some diseases such as apple scab, cedar apple rust, and fire blight can cause the apple tree’s leaves to become curled, discolored, and drop. While some apple tree diseases can be aggressive and tough to reverse, treatments such as pruning and sprays can significantly reduce and prevent their spread.

So, what are the common diseases that cause early leaf loss for apple trees?

Apple Scab

Apple scab is a fungus that creates dark lesions on the leaves and fruit of apple and crabapple trees. Like other tree diseases, apple scab normally appears in the spring and can cause leaf drop into the summer. The best way to prevent and manage apple scab is to prune and pick up any infected leaves and fruit.

Primary treatments for apple scab include pruning, picking up leaves in the fall, and planting apple-scab-resistant trees.

Here are some apple tree varieties that are resistant to apple scab:

• Adams
• Crimson Crisp
• Mac-Free
• Gold Rush
• Royal Beauty

If you believe your apple tree has apple scab, and you’d like more information, check out this resource by the University of Minnesota.

Cedar Apple Rust

Apple cedar rust is a fungus that spreads from juniper trees (also called cedars) to apple trees and causes yellow and dropping leaves. The spores are carried from one tree to another in the spring when it’s warmer and rainy. Cedar apple rust can be treated by reducing nearby juniper trees and by using fungal sprays.

This disease is most common in the Northeast US and especially affects more rural areas that have both farmland and forests. It’s not uncommon for apple trees to be severely affected by this fungus and it can even live dormant during the fall and winter.

After doing some research on cedar apple rust, I found that the recommendation to remove nearby junipers was a bit excessive:

In apple growing areas, junipers are often cut down for a 2-3 mile radius around the production area, or are treated with fungicides to prevent establishment of the fungus on apple trees.

Namely, the problems I saw were:

1. It’s not practical or sometimes possible to cut down all of the junipers in a 2-3 mile radius, especially if you have a smaller property
2. Spraying with fungicides is not a feasible solution for organic apple growers and can often cause more harm to the soil (and therefore—the tree) than it’s worth

So, after some more research, I found that apple trees can still greatly benefit if you remove any juniper trees that are within a 1000 feet radius (sounds a lot better, doesn’t it?). Also, you can help reduce the fungus from spreading if you clear the weeds in at least a 6-foot radius around the apple trees.

Fire Blight

Fire blight (erwinia amylovora) is a highly infectious bacterial disease that affects members of the rose family—including apple, pear, crabapple, rose, cotoneaster, mountain ash, hawthorn, quince, spirea, and pyracantha. This disease causes browning and disfiguring of the leaves and fruit, sometimes killing the tree.

Fire blight is one of the biggest reasons why apple trees get brown leaves. An easy way to tell if your apple tree has fire blight is if the branches have a 180º bend and a scorched appearance (hence its name).

While it can be difficult to treat fire blight, both conventional and organic methods can help control it. Mostly, treating fire blight involves pruning the diseased branches and applying a spray while the tree is dormant as well as when it’s blooming.

If you’d like more information about fire blight and how to treat it, you can refer to my recent post: Fire Blight: The Most Effective and Natural Treatments.

Will Apple Trees Regrow Leaves?

If an apple tree doesn’t have a disease or growing condition, it will regrow its leaves in the early spring. The speed of regrowth depends on the tree’s water, nutrients, and soil pH. Additionally, weather stress can slow the growth of new leaves. For the best chance of regrowth, reduce the stress of the apple tree.

Apple trees are deciduous trees, so it’s normal for them to lose leaves in the fall and winter. Evergreen trees, such as citrus trees, generally keep their leaves year-round.

On the other hand, if your apple tree is losing leaves in the summer, then it likely has a growing issue and requires treatment. Check the above sections for the most common conditions apple trees can get, and if you get stuck, consult your county extension office for more information specific to your area.

How Do You Know if an Apple Tree Is Dying?

The best way to tell if an apple tree is dying is if it’s losing its leaves, blossoms, or fruit during the spring and summer. If the apple tree doesn’t have any leaves, you can check that it’s alive by pruning a small branch and checking for any green inside. You can also consult your county extension office.

Related Posts

If you’d like more information about apple tree diseases and conditions, I wrote a few other posts. Feel free to check them out:

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