13 common apple tree diseases on bark, leaves and fruits

An apple tree is an integral part of the living inventory of local gardens. But if you find out about possible diseases and pests in advance, you will want to throw it away. Too many germs and small animals seek its lifeblood. And yet there are millions of them: the abundant apple tree with the most delicious fruits. Perhaps because many of the dangers are not as serious as feared. Or because the tree, united with its owner, is not helpless at their mercy.

Apple tree diseases

Diseases on bark and wood

If the bark and wood of the apple tree suffer from the diseases described below, the supply of the other parts of the tree also suffers. If the tree is sick, the quantity and quality of the harvest ultimately leave a lot to be desired. Anyone who has not been able to prevent these diseases through preventive measures can only wrest a little more time from them.

Collar rot

The fungal pathogen responsible for collar rot occurs naturally in soils. An infection is caused by this excessive moisture favored. Rainy periods but also heavy soils can lead to unfavorable waterlogging. However, the apple tree only shows the external symptoms from the fifth year onwards.

• the bark is damaged
• small, lazy spots become visible
• expand more and more over time
• the bark sinks in and turns purple
• the wood underneath remains intact

Combat

When the apple tree is sick, any action comes too late. It only helps Prevent:

• Avoid waterlogging and damage to the bark
• Plant less susceptible varieties

Fruit tree cancer

The fruit tree cancer is one of the diseases that is caused by Fungal pathogen caused. During the long course of the disease, various symptoms of the disease can be seen externally:

• cracked and dry bark
• with orange-brown discoloration
• some branches die off
• infected parts show round, orange-colored spore beds
• Strong growths sometimes form on the bark

Combat

Even if the apple tree is sick, it can still live for years and even bear tasty fruit. The disease cannot be completely reversed, but it can be alleviated to some extent by a few measures. The strong growths protruding from the trunk are cut away and the open wounds are sealed with tree wax. You should also remove dead branches.

Root crop

The root goiter occurs even in young apple trees. The causative bacterium penetrates from the ground through open wounds into the roots and makes the tree sick. The flow of sap is reduced, which leads to stunted growth and low crop yields. Especially when buying new trees, look out for the following negative characteristic:

• Tumors on the roots
• partly the size of an apple fruit

Combat

There are no suitable measures that lead to the recovery of the apple tree. If the infestation is severe, it can even die quickly. Prevent it by avoiding open wounds from root damage. For example when digging up. The pathogen can survive undamaged for several years in the soil. Do not plant a new tree at this point for the time being.

Diseases on leaves

The leaves, as the energy supplier for the apple fruits, sprout in early spring. Most diseases in them can be combated well with suitable measures, provided that the signs of the disease are recognized early and correctly interpreted. Then the harvest can still be satisfactory.

Apple powdery mildew

These Fungal disease is treacherous, not just for the one infected tree specimen. Thanks to the easy spread of insects, but also wind and rain, the pathogen can spread to all parts of the tree in no time, as well as to neighboring trees. Then there is a risk of harvest losses or even total failure. The following visible signs of illness can be read off the green of the apple tree:

• white, powder-like coating
• prefers on young leaves and shoots
• rolled up leaves follow, which eventually dry up

Combat

A radical cut of the affected areas is unavoidable, cutting into the healthy wood. Repeat the cut as soon as necessary. In the case of stubborn infestation, sulfur preparations and fungicides can be used. As a preventive measure, keep the apple tree crown airy by taking appropriate cutting measures.

tip: Watch out for dead buds, they are harbingers of this fungal disease.

Apple mosaic virus

Fortunately, this disease got that through one virus is triggered, a rare occurrence. It is not known that the disease is transmitted by animal gardeners, so other trees have nothing to fear. Only edibles may not be taken from these trees. These are the signs of this viral disease:

• Leaves have white to yellowish spots
• Speckles form a mosaic-like pattern
• Illness shows itself only in a few instincts
• in time conquers the whole tree

Combat

There is no cure for this disease. Control is therefore not possible.

Apple scab

Malus domestica, as the botanical name for apple tree is, is often the declared goal of Scab fungi, although some apple varieties are more susceptible and get sick at the beginning of the growing season. A rainy year in the garden accompanied by warmth is ideal for this fungal pathogen, which is why specific attention should be paid to the symptoms of the disease:

• brown discoloration on the leaves
• uneven leaf structure, such as bumps
• dry leaves that fall off in moderation
• later the effects can also be seen on fruits
• they are cracked in places and discolored brown

Combat

From the outset, more resistant varieties should be used or your own apple tree will be strengthened in its resilience. Injections with Horsetail broth and regular thinning of the crown have proven their worth. Affected parts have to be cut into the healthy wood and infected leaves have to be collected and disposed of. If these measures don't help, a fungicide can also help if the infestation is severe.

tip: The fruits remain edible, the unsightly areas can be cut away. The cracked areas make it easy for rot fungi to penetrate, which is why long storage no longer works.

Fire blight

If the fire is raging, no "attempt to extinguish it" can stop it. This Bacterial infestation is one of the most serious diseases that Malus domestica can afflict.

• young shoots are affected
• also flowers
• turn completely brown to black
• but stick to the tree
• the tree looks burned

Combat

The spread of fire blight is easily possible due to the large insect population but also by humans. probably. Fire blight usually leads to the death of the apple tree. Because of these two circumstances, the fire blight is notifiable in this country. Inform the responsible office as soon as you discover the signs listed above on a tree. Control is not possible, but in the early stages the tree can be cut through very large pruning measures. still save, otherwise it should be cleared and completely burned.

tip: Inquire about resistant apple varieties when replanting.

Monilia - peak drought

If the Monilia mushroom spreads on leaves and flowers, one speaks of the so-called peak drought. This disease is clearly shown:

• meager, withered leaves
• at the shoot tips

Combat

Immediately cut back infected branches to at least 30 cm in healthy wood. Regular clearings reduce the infestation pressure. As a preventive measure, organic plant strengtheners are injected every two weeks from the shoot.

Diseases that damage fruits

Apple fruits that are clearly marked by illness can no longer be transformed back into healthy specimens. Then the only thing left to do is to distinguish between what is still edible and what must be disposed of. The next step is to find out the causes and fight them as best as possible so that the harvest in the following year does not suffer the same fate.

Glassiness

At this Metabolic disease the causes have not yet been fully clarified. However, calcium deficiency, too much sunlight and an imbalance between the number of leaves and the amount of fruit are suspected to be favorable factors. The sliced ​​apple doesn't look appetizing. However, consumption is not harmful to health. Only the taste can suffer. In this case, however, the apple can still be processed into puree or something similar.

• Apple produces too much sugar
• The pulp is glassy and watery
• mostly around the housing
• freshly harvested apples affected
• Glassiness is partially reduced after storage

Combat

Avoiding glassy apples starts with the planting by choosing a less susceptible variety and a slightly more shady location. Cut back heavily overgrown green on the apple tree, leaving enough leaves to protect from the sun. Also pay attention to a calcium-containing fertilizer.

Calyx rot

If the apple fruits show damage in the calyx area, the calyx rot is up to mischief. It is often referred to as core rot. Most of the time, damp weather created favorable conditions for her. the infection with the pathogen has already taken place during flowering and I visibly show it in the harvest time.

• dark brown spots in the calyx area
• dry and sunken
• inside, the core is brown and putrid
• The pulp may also rot during storage
• infested fruits ripen earlier
• fall from the tree prematurely

Combat

Infested fruits are promptly and completely collected and disposed of. You should only take suitable measures if the collar rot recurs on your apple tree over the years. Spray preventively during flowering in damp weather.

Monilia - fruit rot

Humid weather combined with a thick canopy of leaves ruins the apple harvest to a great extent. Of the mushroom then spreads very quickly, with small pricks of the codling moth and apple saw wasps providing ideal access.

• healthy fruits turn into fruit mummies
• turn brown with white mold spots

Combat

Collect and dispose of all infected fruits promptly so that the fungal pathogen cannot spread any further. Under no circumstances should the brown fruits end up on the compost heap. But also fight the above-mentioned pests, which contribute significantly to an unfavorable course of the disease.

Soot Spot Disease

In private gardens, where preventive spraying with fungicides is not the order of the day, soot stain is one of the most common Fungal diseases on apple trees.

• spots of different sizes on fruits
• greenish-black color
• cannot be completely removed by rubbing
• heavy infestation covers the whole fruit with a black coating

Combat

Since the fungus can also be affected by moisture or If raindrops are spread, an airy crown must dry off quickly. Therefore dense branches have to be thinned out. Sprayings against apple scab work at the same time against the causative agent of the soot stain disease.

Stippling

This too Metabolic disease presumably causes a calcium deficiency. At the same time, increased levels of magnesium and potassium are found. A calcium deficiency in the soil does not necessarily have to prevail; rather, its transport in the tree is crucial. This is not optimal for some varieties. The symptoms only show up on the fruits and have to be accepted for the current harvest.

• The flesh has brown spots
• often only show up during storage
• the apple aroma is still edible at first
• but becomes more and more bitter over time
• Jonagold and Boskop are particularly vulnerable
• the apple variety Golden Delicious less

Combat

Trees with little bearing should experience a reduction in foliage through a summer pruning. From July onwards, the fruits can be treated several times with 0.5% calcium chloride injections.

tip: Pick a few apples about two weeks before harvest and store them in plastic at about 30 ° C. If the symptoms of the disease then show up, longer storage should be avoided.