Apricots or apricots grow as a shrub or small tree with heights of up to 600 cm. The four to eight centimeters large, light yellow to orange-colored, velvety hairy fruits develop from the flowers, which by the way appear before the leaves. In July the apricots are ripe and can be harvested. Unfortunately, they are quite sensitive and, like the entire apricot tree, can therefore be attacked by various diseases.
Diseases on the apricot tree
The Prunus armeniaca is a sensitive wood and very susceptible to diseases. It is sensitive to frost and constant rain, which can favor fungal diseases such as monilia, scab or shotgun. Both flowers and leaves as well as fruits can be affected. This in turn endangers the health of the apricot tree. Some of these diseases are particularly common on the apricot tree.
Sharak disease
Sharka is the most important disease for the apricot tree. The pathogen is a virus that can lead to various types of damage, which can vary in severity. An infestation shows up in July / August by ring-shaped or cloud-like lightening on the leaves. The growth of affected trees is inhibited. Infested fruits on the apricot tree look scarred, with pox- and groove-like deformations, they are inedible. In the affected areas, the pulp is reddish in color and has a rubber-like structure.
In general, viral diseases cannot be combated. Affected trees usually have to be cleared and burned. As a preventive measure, you should pay attention to less susceptible varieties when buying appropriate plants.
Frizziness
- Curl disease in the apricot tree caused by a hose fungus
- Fungus feeds on dead plant parts
- nests on the shoots
- explosive spread after a damp and wet winter
- an already weakened apricot tree is particularly endangered
- first signs of frizziness in spring
- young leaves begin to curl
- later light green to reddish spots on the leaves
- Leaves keep turning
- turn whitish, look a bit rubbery and fall off
To combat this, a fungicide that is especially effective against this disease is available commercially. However, this can make the fungus resistant. It is harmful to aquatic organisms and is suspected of causing lasting damage to bees. What you can do is thoroughly remove any affected branches, shoots, and leaves. Clippings should not be disposed of on top of the compost, but packed airtight in the household waste. As a preventive measure, you should pay particular attention to the correct location for the apricot tree.
Shotgun Sickness
- Shotgun disease manifests itself in small, round leaf spots
- mainly on young leaves
- Spots turn reddish to brown in the further course
- affected leaves later perforated
- fall off prematurely
- Affected fruits have round, reddish-edged, slightly sunken spots
- they cripple and dry up
- there is a strong flow of rubber
- The causative fungus needs a moist environment
- spreads particularly strongly in a cool and rainy spring
If an infestation is recognized, the affected branches should be cut back radically. All clippings must be completely removed and disposed of accordingly. It is best to pack it in airtight bags, because a small gust of wind is enough for the fungal spores to colonize the tree again. Preparations with copper, network sulfur or clay promise good effectiveness. If the infestation is severe, the use of a special fungicide is essential. You can prevent it by removing fallen leaves and taking regular pruning measures.
Bacterial fire
Bacterial burn is also one of the diseases that can affect the apricot tree. The symptoms of an infestation are varied and easy to confuse with shotgun disease. These include small brown spots on the leaf margins, blackish spots on the fruits, shoot deaths and bark necrosis (visible depressions). In addition, the tree excretes more resin.
A direct fight against this fungal disease is not possible. This makes preventive measures all the more important. These include, for example, a sunny and airy location, the whitening of the trunk and preventive spraying with preparations containing copper. Cutbacks should be limited to regular thinning of the crown and larger cuts should be avoided as far as possible.
Monilia
Monilia is an important flower disease in apricots. It can be recognized by the dying shoots and flowers. An infection of the flowers is favored by cool, damp weather during flowering. Affected flowers wilt and, together with the neighboring leaves, turn brown within a few days. In the further course, the shoot tips die off, on which yellowish-gray spore beds later appear. Sick fruits stick to the tree as brown or black fruit mummies. With increasing ripeness, the susceptibility of these stone fruits also increases.
To combat it, it is particularly important to remove diseased fruits and all fruit mummies from the tree and the ground as quickly as possible and dispose of them. The same applies to diseased branches, which should be cut back into the healthy wood. Direct control is also not possible with this disease.
Black sooty mildew
The sugary excretions of aphids on the leaves are responsible for black sooty mildew. Harmful fungi grow on them and turn black. If necessary, the leaves can be completely blackened so that they can no longer absorb sunlight. One can counteract the sooty mildew by combating the aphids.
Verticillium-Which
- Verticillium wilt is caused by wilt fungi living in the soil
- Fungi clog the waterways of the trees
- can survive in the ground for up to fifteen years
- Leaves wither and fall off despite sufficient water supply
- sporadic death of shoots, later also of twigs and branches
- Combating is extremely difficult
- Remove any fallen leaves from the ground
- Fungi form new organs of persistence in the leaves
- Cut off dead twigs and branches directly at the roots
- leave no stumps on the tree
- Cut diseased twigs or branches back into the sound wood
- Pay attention to optimal fertilization and good soil conditions as a preventive measure
Rubber flow
The rubber flow can be recognized by a sticky, amber-colored mass that is reminiscent of the resin of conifers and emerges from the bark and branches. This can be triggered by unfavorable growth conditions, severe frosts, bacteria, fungal infections but also damage to the bark. Unfavorable cultivation conditions, in particular heavy, waterlogging and sandy-dry soils can also promote the flow of rubber on the apricot tree. Young and older as well as already weakened trees are particularly susceptible to this phenomenon.
- start treatment early, around the end of February
- Cut out the affected areas with a clean, sharp knife
- Then close the wounds with tree wax
- Wound care, even the smallest wounds advisable
- Apricot tree should not stand on soil that is too moist or sandy
- Liming the trunk of the apricot tree in autumn
- this protects cracks in the bark from damage caused by the cold
- Fight diseases such as shotgun and frizz disease early on
Powdery mildew
Powdery mildew is characterized by a white, floury coating on leaves, shoots, flowers and fruits. The responsible fungus removes vital nutrients from the apricot tree, so that growth is disturbed. Injections with non-containing preparations are ideal for treatment. An infestation can be prevented by regular pruning measures so that the inside of the crown is well ventilated at all times. Furthermore, one should not fertilize with too nitrogen emphasis, pay attention to a loose soil and prefer resistant varieties.
Valsa disease
- This disease is caused by wound parasites
- need dead tissue to infect
- penetrate the wood through injuries in autumn / winter
- Pathogens attack the infection sites at the start of vegetation
- Signs of infestation, brown, wilting leaves
- branches and twigs also dry up
- gum flows out of the bark
- Affected areas of the bark sink in
- there are wart-like, black fruiting bodies
- there are brownish rot spots on the fruits
- with gray or yellowish-brown pustules arranged in a ring
The most effective protection against an infestation offers both a regular cut outside of the main infection time and a proper wound closure. Infestation can be reduced by spraying with a copper-containing preparation that is used at the beginning and during an infestation.
Conclusion
Due to its need for warmth, the apricot tree is one of the exotic fruit trees. It is demanding in terms of location and maintenance and therefore relatively susceptible to a wide variety of diseases. Then it is important to recognize these and initiate countermeasures as early as possible. Prevention is a factor that should not be underestimated.
