Diseases and pests of walnut: causes and methods of control, how to treat and what to do

One of the popular crops, which gives a valuable nut, is difficult to grow. In addition to favorable conditions, walnuts need careful care in compliance with the rules of agricultural technology. If you deviate from the rules, you will have to deal with walnut diseases and pest infestation. In this case, you can lose the crop, as well as the unique tree.

Causes of diseases and pests

Many factors cause disease in walnut crops. You can determine what is happening to the tree by the state of the bark, leaves, fruits.When the leaves of a walnut turn black, this means that a serious infection has struck the plant. It must be de alt with immediately. Pathogenic microorganisms remain active for a long time, waiting for suitable conditions for reproduction.

They attack those plants that are planted in the area where:

• little light;
• waterlogged soil due to close groundwater;
• soil acidity is high;
• soils are poor in nutrients.

A nut that is weakened by winter cold, spring frosts is attacked by fungi, bacteria, and insect parasites. Such walnut specimens do not bear fruit, constantly getting sick.

What can catch a walnut

Infectious diseases lie in wait for plants at every turn. If there are trees in the garden with tissues damaged by pathogenic bacteria, fungi, then neighbors also become infected from them.You can determine the type of disease by certain signs. Then a systematic struggle should take place taking into account the specifics of the infection, the characteristics of its course.

Bacteriosis

In the spring, when it's warm and damp, you need to carefully examine the walnut trees. Awakened insects can transfer pollen with pathogenic bacteria from one plant to another. Bacteriosis is manifested by dark spots on leaves, fruits, shoots, flowers. The period of walnut pollination is especially dangerous with an increased likelihood of infection through pollen.

The result of the action of bacteria will be the loss of the crop, as the flowers and ovaries will die. But the young fetus is also exposed to pathogens. Then he shrinks and falls off. And all parts of the plant turn brown.

Bacterial burn

The rapid development of an infectious disease leads to the death of a tree.Looking at a sick plant is scary. It seems that the crown, the trunk - everything is burned. Black color becomes dominant on the leaves. Young shoots stop developing, dry up. The kidneys are dying. The inside of the fruit turns black. Cankers on the entire aerial part of the nut spread more rapidly during periods of rain. It is very difficult to save a plant if the disease has become advanced.

Brown spotting (Marsoniosis)

Marsonia fungus causes spotting on leaves, fruits of culture. First, in May, yellowness begins to appear on young leaves. Small spots grow, turn brown. When they merge, the leaf falls off. The ovaries are also covered with reddish-brown dots. Nuts cannot be consumed internally, as the kernel deteriorates and dries. Half of the horticultural crop suffers from the consequences of the infection.

Root cancer

Rod-shaped bacteria manage to survive the winter in the soil to start reproducing in the spring.Through the penetration of bacteria into the roots of the walnut, the infection of the plant passes. And the gates of infection are cracks, wounds on the surface of the root system. Under the action of bacteria on the tissues of the underground part of the nut, growths and influxes form.

You can notice the pathology by the delay in the growth of a walnut. Cancer is diagnosed by digging up a tree and examining its roots. Only timely medical measures will save the tree from death.

Insect pests of nuts

A weakened walnut is often the target of garden pests. Insects try to lay their eggs on the leaves, in the bark, the fruit. It is difficult to notice some of the parasites, so you need to know how the results of their vital activity are reflected in the culture.

American white butterfly

A dangerous pest of a hazel plantation is an ordinary butterfly with white wings, sometimes decorated with dark dots.Having laid eggs on leaves and shoots, the female causes great damage to the tree. The voracity of the caterpillars that were born is great. They can destroy all foliage and young growth. Having passed to the neighbors, the larvae of the parasite continue their activity. During the summer, the female makes 3 clutches of eggs, so the number of caterpillars only increases.

Sapwood

Weakened specimens of the walnut culture are attacked by a black bug, the size of which varies between 3-4 millimeters. It has a black head and brown elytra. Beetles fly intensively in June. It is difficult to see the larvae of the beetle, as they hide under the bark.

If the wood is damaged, then the larvae of the sapwood make their way inside. There they, gnawing passages 6 centimeters long, move to the kidneys. They feed on them. Hence the decrease in the yield of the nut, the flow of gum. For young plants, the sapwood is dangerous because it damages their trunks.

Halnut Warty Mite

Fungal plant diseases cause gall mites. Pest attacks increase during periods of wet summer. You can detect an insect by the fact that:

• bloating appears on the sheet;
• young shoots stop developing;
• branches, leaves begin to dry;
• a thin cobweb is visible from the underside of the leaf plate.

Reproducing, the mite destroys walnut plantings. The fruits are getting smaller and the trees are weakening.

Nut Moth

Danger to walnut seedlings is a small butterfly with grayish-brown wings. The larvae that emerge from the eggs of the moth eat the delicate stems of the plant. If the caterpillars parasitize on mature trees, they destroy green leaves, feeding on the juicy middle. Therefore, the leaf becomes yellow, dries up and falls off.

Codling moth

A small moth harms the garden in the caterpillar stage. At first the larva has a dark gray color, then pinkish-white. The caterpillar feeds on young walnut fruits. Having bitten through the skin, she climbs inside, eating out the pulp. A dot on the surface of the nut indicates infection with the codling moth. For the winter, caterpillars in dense white cocoons hide under lumps of soil, in cracks in the bark. In spring they turn into pupae. In June, a butterfly flies out of the chrysalis.

Disease and pest control methods

Spring begins the reproduction of spores of pathogenic fungi, so it is necessary to treat the walnut before the leaves bloom. The main remedy will be Bordeaux liquid or preparations with a high content of copper.

The second treatment should be carried out if the spots on the leaves have increased in size. Spray the crown twice more every 2 weeks.

It is useful to process trees before the appearance of inflorescences. After harvesting, you can spray with preparations such as Zineb or Hom.

Disease control techniques include:

• pruning damaged shoots, leaves;
• destruction of fruits if they have turned brown and shriveled;
• carrying out activities until the plant is completely cured;
• burning all plant residues in autumn;
• digging the soil in the garden in spring and autumn.

To protect against pests, both insecticidal preparations and traps are used. The number of codling moths in the garden is determined by how many individuals fall into traps. Pheromone traps and food traps are used.

As a bait, sweet juice of fruits, berries, slightly fermented, is suitable. They are placed in a trap on the tops of trees.If there are a lot of butterflies, then it is necessary to treat the trees with pesticides. Poisons were used before caterpillars appeared. Then it will be more difficult to deal with the pest, its offspring.

Before winter, carefully inspect the bark of trees, covering damage, cracks with garden pitch. It is necessary to destroy the pupae and caterpillars hiding under the bark. They clean the bark of walnut trees where the sapwood beetles have made their moves. It is imperative to remove mosses and lichens from walnut trunks.

From pests, protection consists not only in chemicals, but also in biological agents. Safer insecticides based on avermectin. It is allowed to use the means of the thiacloprid group, chloranthraniliprole.

If you soak the branches well with insecticidal preparations during processing, the number of pests will decrease.

Prevention measures

It is possible to prevent diseases and pests on a walnut by a complex of agrotechnical, biological measures:

1. Annual thinning of the crown, removal of diseased and damaged branches will increase the illumination of the tree.
2. Several times during the growing season loosen the ground between the rows, removing weeds.
3. Inspecting a walnut for nests of caterpillars and beetles will stop their reproduction.
4. Timely feeding will help grow he althy plants.
5. As a preventive measure, spraying Bordeaux liquid three times, starting in early spring.
6. For a tree to bear fruit well, it is necessary to treat it from fungal and bacterial infections in time.

You should not wait for the leaves of the walnut to turn yellow, you need to water and fertilize the plant on time. Be sure to ensure that there is no damage to the bark, shoots of the nut crop.

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