Causes and signs of hazelnut diseases and pests, what to do to combat them

Growing any garden crop does not go smoothly. Pathogenic fungi and harmful insects infect fruit tree plantings as a result of inept care, weather and climatic anomalies. The specificity of hazelnut diseases is such that they must be dealt with based on the symptoms of the pathology. Some of the diseases are characteristic only of nut crops, so few summer residents know about them.

Why do they arise?

The causes of hazelnut ailments include:

• the plant is not properly cared for;
• there are no growing conditions for the crop;
• soils are swampy and saline;
• little light.

During periods of humid and hot summer, the activity of pathogenic fungi increases, hence the high threshold for disease in hazel trees. The carelessness of the gardener allows one not to notice white spots on the leaves or yellow or brown ones. And this is the first sign of a fungal infection. It is easier to fight a disease that is detected in a timely manner. Neglected pathological conditions lead to the death of a walnut plantation.

Hazelnut diseases and pests

It is typical that the causative agent of the main hazelnut diseases causes infections in other fruit crops. Hazel plantings often suffer from powdery mildew. Aphids can also live on tree leaves. But there are specific diseases that are found only in nut crop plantings.

Diseases

Hazel suffers from many infections caused by fungi. Viral diseases are rare for the plant.

Powdery mildew

According to research by scientists, this disease occurs on crops more often than various types of spotting. The yellow aphid provokes the development of the disease. Leaving its excrement on the surface of the leaves, it attracts pathogenic fungi to the plant. With further development, powdery mildew grows into whitish spots containing mycelial spores.

They are visible to the naked eye on the surface of the leaves.The main factors provoking the disease are high air humidity and temperatures above 28 degrees Celsius.

Conidia, having overwintered in the hazel buds, infect the plants. Although many hazelnut varieties are resistant to the fungus, regular spraying is needed to stop the spread of the pathological process.

Phyllosticosis

The disease caused by the fungus is called yellow-brown leaf spot for good reason. Necrosis of plant tissue is manifested by large spots of irregular shape. A border is visible along their edges, and dark dots form inside. Over time, the affected part of the leaf cracks and falls out. In neglected conditions, the leaves begin to turn yellow and fall off.

The consequence of infection with phyllostictosis will be weakening of the shoots and their poor ripening. A sick hazel tree may not survive the winter. To prevent the infection from spreading to neighboring trees, it is necessary to collect and burn fallen leaves.

Ocher-brown spotting

The leaves on the hazelnuts become covered with brown spots. Then they become white, and black dots, the so-called flattened pycnidia, are scattered on top. The consequence of fungal pathology will be drying out and falling leaves. But fungi remain active in fallen leaves affected by infection.

Rainy, warm weather favors the development of the disease. The pycnidia swell, releasing pycnospores. The wind carries the sinuous slimy masses to neighboring plants. Insects help fungi reproduce.

Red-brown spotting

The spots on the leaves are initially reddish, gradually turning into yellow cushions. They contain spores of a pathogenic microorganism. The result of the action of the fungus is a delay in the growth and development of hazelnut shoots. The bush weakens and bears little fruit.

The disease appears more often in the southern hazelnut growing zones. In the gardens of Siberia and the Chernozem region, the fungus rarely spreads, although it can be registered on hazel.

Cylindrosporiosis spot

Cylindrosporium fungi cause numerous spots to appear on the surface of leaves. They are either round or with corners. Spores collect on the upper side of the leaf in brown pads. In humid-hot weather, the pads burst, allowing the spores to spread to other crops.

Cercospora spot

The disease is different:

• a large number of spots;
• red-brown dots;
• merging of spots into one grayish area;
• an inconspicuous coating of mycelium with spores around the edges.

If the brown dots are 1-3 millimeters in diameter, then the spot into which they combine can cover the entire surface of the plate.

Black spot

Another name for the disease is Phomopsis. It is dangerous because it affects all parts of the plant. Pathology is determined by:

• discoloration of woody shoots;
• dark spots on the bark;
• dying of branches;
• brownish spots with a lightened center on the leaves.

Plaque on the surface of the leaf blade indicates the spread of the disease by spores. A diseased tree infects neighboring ones, as spores are carried by precipitation, wind, and insects. The nut stops developing, blooming, and bearing fruit.

Pests

There are also many insects that attack hazelnuts and hazelnuts. Some of the pests are parasitic, feeding on the juices of the leaves, while others feast on the tasty fruits of the tree and their pulp.

Birch cushion

The pest is a small-sucking insect. It has a convex body up to 8 millimeters long and 3-4 mm wide. Adult insects are motionless, but their offspring, the larvae, cause great harm to the hazel tree. They feed on the juice of hazelnut bark.Overwintering under it, they continue to harm the nut in the spring. Females develop a mealy egg sac measuring up to 1 centimeter, which looks like a pad. In mid-summer, the female lays up to 600 eggs in it. They are less than 1 millimeter in size and red.

The pest is most often found in the European part of Russia, southern Siberia, and the Far East.

Green garden bug

Every summer resident has encountered the garden bug. A very mobile insect with a shiny green body and leathery fore wings. The bug is a sucking pest. The larvae are similar in appearance to the adults, but are light brown in color. They affect all parts of garden plants. Due to the action of adult insects and larvae, hazelnut leaves become wrinkled, turn yellow, and the inflorescences fall off.

Hazel weevil

You can recognize the pest by its long proboscis. The black bug has a body 6-8 millimeters long, and a nose - 4. Yellow-gray scales give the insect a light shade. During the winter, weevil larvae burrow into the ground, where they pupate. In spring, beetles find food on hazel. And the female lays eggs in the pulp of the set nuts. This is where the parasites live, eating the insides of hazelnut fruits. The larvae live for 25 days.

No hazelnut varieties have been developed that are resistant to the weevil, so the pest must be combated everywhere.

Hickory pipe gun

The beetle, 6-7 millimeters long, is distinguished by its black body and red back. The structure of the insect's head is interesting: it is elongated like a tube with an extension at the top, and seems to be drawn out from the sides. The white, thick larvae of the tubeworm are inactive and feed on the green parts of the plant. The eggs are laid by the female in a hazel leaf rolled into a tube. The leaves begin to dry out and fall off.

Walnut longhorned beetle

One of the dangerous pests that can destroy walnut plantations begins its activity in early May. Flying around its territory, an insect with long black antennae lays eggs under the bark of a hazelnut. Already in June, the emerging larvae begin to gnaw the branches of the bush. The shoots dry out, and the foliage turns yellow and falls off. The pest can be identified by the curling of leaves in the upper parts of the bush. Although the root remains alive, the plant is not able to be reborn again.

After wintering, the larvae infect 2-3 year old shoots. By gnawing passages in the branches, they lead to the drying out of most of the shoot.

Alder leaf beetle

This bug is dangerous for industrial hazelnut plantations. You can identify it by its black legs and antennae, and the elytra have a purple tint. In April, beetles appear on hazelnuts when they wake up after hibernation. The parasite attacks hazel leaves, which it eats with lightning speed. The larvae are born from eggs laid on the plant. Their life span is 25 days.

Northern birch sawfly

Hymenoptera larvae hatch from eggs laid on the underside of the leaf. Dirty green false caterpillars are so voracious that they can completely eat up an entire hazel. Moreover, they appear twice during the summer: in May and from July to September.

An adult insect with a shiny black body and transparent wings feeds mainly on birch leaves. You can see sawflies in early summer when they fly around the garden. Females cut the underside of the leaves and lay 1 egg in them. Caterpillars pupate in the ground where they overwinter.

Hazel moth

If a small butterfly with narrow silvery wings flies around a tree, then it is a moth.Its larvae damage hazel leaves by gnawing into the thickness of the leaf. Having eaten away a significant mine visible from the bottom of the leaf, the larva moves to the upper part. At the same time, the leaves become marbled-spotted in color. Larvae live in mines and transform into pupae, remaining in this stage for only 8-9 days. In July-August, a butterfly flies out of a fragile cocoon.

Hazel snake moth

A butterfly with beautiful fringed hind wings is not dangerous itself. But its larvae, having appeared on hazelnut leaves, make passages inside the plant tissues, similar to the trail of a snake. This pattern, decorated with parasite excrement, can be used to identify the pest. After 3 weeks, the caterpillar emerges from the leaf, falling to the ground. It pupates and overwinters in the ground safely until spring.

Hazel pocket moth

The butterfly is small, a little more than 1 centimeter, with silvery wings and a fringe behind them. The larvae hide in curved leaves, like pockets, feeding on their juices. They hold the parts of the shelter together with sticky webs. Inside the leaf, tissues are eaten away and become skeletonized. During the period of its development, the caterpillar makes up to 4-5 pockets. In dry and hot summers, moths cause significant damage to hazel trees.

Methods for controlling insects and diseases

Time must be devoted to pest control on a walnut plantation in order to save the crop:

1. As soon as the hazel leaves begin to bloom, spray with Fufanon or Kemifos.
2. Suitable for exterminating pests "Karbofos", "Fozalon".
3. The treatment is carried out twice more on those trees on which pests are found.
4. The leaves rolled into a tube are collected by hand.
5. Shake weevils and bugs onto the ground, first laying down a sheet of cellophane or non-woven material. Then they are destroyed.
6. It is necessary to burn plant residues in the fall, as well as dig up the soil, in order to destroy the pupae and larvae of parasites.
7. After the snow melts, cut off the dried branches 10-15 centimeters below the drying level.
8. Continue pruning in July-August, capturing 2-3 healthy leaves.
9. In the spring, before the insects emerge, it is necessary to treat the soil with 10% Bazudin, embedding the granules into the ground.

The method of combating hazelnut diseases is the same: treating the affected plants with fungicides. In the spring, when the buds swell, spray with Bordeaux mixture at a concentration of 1%. Walnut bushes damaged by fungi can be treated three times with Abiga-Peak.

To combat many fungal infections, preparations containing copper are used. Among folk remedies, the use of herbal infusion is effective. To prepare it, take dry grass and add warm water in a 1:1 ratio. You need to keep the solution for a week, then filter it and spray it on walnut bushes. It is better to carry out treatment in the evening.

If hazelnuts drop fruits, they must be collected and destroyed. They are damaged by pests that can destroy all the trees. Among the methods of combating diseases, one can highlight loosening the soil between the rows in spring and autumn. Digging up the area will save you from diseases and pests.

Prevention measures

It is easier to prevent diseases than to find a way to get rid of them later. Prevention measures include:

• carrying out timely watering and fertilizing of hazel and hazelnuts;
• removal of damaged shoots;
• pruning branches that thicken the hazel crown;
• regular inspection of plants;
• protecting them from frost, heat, and high humidity;
• digging the soil in spring and autumn.

A nut plantation can only be preserved through competent agrotechnical measures. To ensure the health of hazelnut plantings, do not plant birch or alder nearby. Pests of these trees can migrate to the hazel tree and destroy it. If an infection has occurred, then you need to get rid of the plant where the pests have settled, as if it were the source of the disease. Or you can choose another place on the site for the hazel tree.