Originally, the heat-loving apricot tree comes from Armenia and China. Today it is widespread in our regions and is sometimes known as the apricot tree. It is not only so popular because of its sweet fruit, but it is also relatively easy to care for. This is because apricot trees do not make great demands on the soil. But they love a warm location, protected from rain and wind. However, only in dry periods should be regular watering. In early summer, sometimes in dry weather and high temperatures, the leaves on the apricot trees can hang limply, begin to wilt and eventually fall off. In this case, it is necessary to get to the bottom of the causes.
Withered leaves not due to lack of water
At first glance, such a sight can quickly assume that a lack of water causes the leaves to wilt and dry up, since this phenomenon usually occurs during dry periods. But even watering can not help the tree here. The plant continues to dry out slowly. The cause of this may be a sign of various diseases, such as:
- Verticillium wilt
- Monilia laxa
- Verticillium wilt
This disease is caused by the harmful fungi Verticillium dahilae (dark microsclerotia) and Verticillium albo-atrum (permanent mycelium). Their fungal spores can survive in the soil for more than ten years without a host plant. They enter the plants through the roots, for example after root pruning, where they form toxins and eventually clog the tree’s water conduits. Signs are:
- Leaves wilting to the point of falling off
- Reduction of leaf growth
- cracking of branches and shoots
- Balding and death of individual shoots, later also of entire branches
- Death of the whole tree after a few years
- Occurrence at the beginning mostly only on one side
- Additional occurrence of leaf yellowing and necrosis possible
- Sluggish disease progression
- Dry periods and high temperatures accelerate the course of the disease
- Fruits are small, partly inedible
- Clear detection only by laboratory examination of the soil
Tip: By scoring the bark near the ground or on affected shoots, water lines lying lengthwise underneath are discolored brown.
No fungicide use possible for Verticillium wilt.
So far, no direct control of the harmful fungi by chemical means is possible. When the first symptoms become visible, the following action should be taken:
- Carefully rake up fallen leaves, dispose of them in household trash
- Remove dead branches and twigs directly at the base
- Do not leave stumps
- Close cut wounds
- Cut back diseased shoots far into the healthy wood, at least 50 cm
- Use clean and sharp cutting tools
- Carry out pruning operations in dry, sunny weather
- Completely remove dead trees
- If necessary, renew soil
Tip: Ring-shaped dark discoloration in the area of the conductive tracts indicates Verticillium wilt on a branch that has been cut crosswise.
Apoplexy in apricots is also known as strike strike. Apricot trees can die within a very short time. The cause may be cold damage due to winter or late frosts. These lead to damage to the conductive pathways under the bark. This is particularly critical in the case of apricots, as they are the first to end their winter dormancy, and late frosts usually still occur. However, a heavy fruit crop in the previous year, occurring bacterial blight, shotgun disease or Monilia laxa can also favor the occurrence of “apoplexy”. First signs of apoplexy:
After initial sprouting, wilting leaves and shoot sprouting.
Encroachment on individual twigs, branches or the entire crown
Typical gum flow underneath wilted parts (blockage of conduction paths)
Bark torn open on strong branches and in the trunk area
Highest mortality rate between 3rd and 7th standing year
Strengthen tree health and frost resistance
Take immediate action at the first signs of apoplexy.
Remove dying branches at the end of May
However, stress due to high fruit set or vigorous growth in the absence of yield.
Balance fruit thinning, at least one fruit per hand width
When planting new apricots, make sure they are frost-hardy rootstocks
Monilia laxa is also known as lace drought. From budding to after flowering, infection with the fungus Monilia laxa occurs. In this process, the mycelium spreads rapidly and penetrates the fruiting wood. Similarly, the top drought is favored by a precipitation-rich weather. However, the fungal spores can also overwinter on the dried leaves, twigs, and fruit mummies on the tree. Because they have a high germination capacity, rapid multiplication occurs in the spring after flowering. They are then spread by rain, wind and insects. Attention should be paid to the following symptoms:
- Blackening of the flower stigma
- Pale green leaves on annual wood
- 3 to 4 weeks after flowering wilting of shoot tips, flowers and leaves
- encroachment on entire branch sections, leading to tip drought
- Gum flow at boundary between diseased and healthy tissue
Pruning in case of infestation
To avoid further damage, action must be taken as quickly as possible in the event of Monilia laxa infestation.
- Chemical treatment is no longer possible in case of infestation
- Cut out all infested branches, infected flowers and fruit mummies
- Pruning of dying branches down to 30 cm into the healthy wood
- Preventive fungicide spraying (fungus-free Ectivo or Duaxo Universal fungus-free)
- In addition, spraying at full bloom
General prophylactic measures
In order to avoid an outbreak of the disease from the outset, a number of things should be taken into account. Because here it is advisable to combine various preventive measures. Then nothing stands in the way of a bountiful harvest of the delicious sweet fruit for years to come.
- Choose an optimal location, light, well-drained soil in a sheltered position.
- Avoid soils with waterlogging, improve if necessary
- Do not plant too deep, do not damage roots in the process
- Use tree snorkel when planting
- If necessary, lower the pH of the soil by adding grape pomace, conifer compost or peat.
- If necessary, replace the entire soil
- Soil improvement by incorporating active plant substances (for example radish or mustard plants)
- Balanced water and nutrient supply
- Avoid drought stress by watering regularly
- Fertilization with compost, patent potash or horn meal and shavings
- Avoid nitrogen fertilization
- Regular thinning and pruning
- Immediately close open pruning wounds
- Do not leave branch stubs and fruit mummies standing
- Proper variety selection, such as Goldrich, Sylvevcot, Bergarouge, Harlayne.
Tip: Tree snorkels are jute bags filled with expanded clay, for good root aeration. To avoid root damage in the event of subsequent installation, it is advisable to hire a specialist company.
Plant strengthening through natural remedies
Only healthy and strong trees have good resistance to diseases. However, to maintain health and at the same time strengthen the plant cells, additional biological tonics can be administered. For this purpose, fomentations from field horsetail, stinging nettle, tansy, comfrey or wormwood have proven to be effective. These can be produced quickly and without much effort, such as a liquid manure from field horsetail:
- 500g fresh field horsetail with 5l water pour over.
- Let brew for 3 hours, heat up, simmer for 30 minutes.
- Strain after cooling
- Use every 2 weeks for at least 4-6 weeks
Tip: In the specialized trade preparations from algae extracts and essential oils are also available to strengthen the resistance. But in addition, there are also inorganic tonics, such as silicates, carbonates and phosphorus and potassium salts.