Wheat diseases: a description of the main, which pests affect, resistant varieties

Cereal diseases can be ubiquitous and cause great harm to those who grow cereals. Diseased plants grow and develop poorly, the yield drops. Consider the varieties of the main diseases of wheat, fungal and bacterial, their signs, pests of this crop. Which varieties of this type of cereal are considered resistant.

Fungal diseases

Pathogenic fungi are the causative agents of a number of crop diseases that are difficult to cure and lead to a deterioration in the condition of plants. Some diseases develop on young plants, their signs can be detected already in the spring, on spring or winter varieties, while others affect cereals during the season.

It is estimated that approximately 80% of the grain harvest is lost due to fungal diseases. Fungal infections rank first among all plant diseases in terms of damage, frequency of occurrence and diversity of pathogens.

Fungi are heterogeneous in terms of the level of organization. Most plant pathogens belong to the group of marsupial fungi. Some species affect only 1 type of crops, others several. A pattern has been noticed: the more “specialized” the fungus is, the more aggressive and harmful it is.

Fungi are able to interact with plants in various conditions: in the aquatic or terrestrial environment, in different climatic conditions. Damage by parasitic fungi leads to a decrease in plant immunity, unfavorable conditions and non-compliance with growing technology, failure to carry out timely preventive treatments with drugs.

Rust

Sources of infection are spores remaining on the remains of wheat, rye, barley and perennial grasses of the cereal family: bluegrass, couch grass, fescue. Infection occurs at a temperature of 15-25 ° C, high air humidity of 95-100% and in the presence of drip moisture on the leaves for 3-5 hours. The damage of wheat rust is to reduce the photosynthetic surface of the leaves, their rapid drying, and the formation of lean grain.

Smut

Wheat is affected by several types of smut, more common are hard, dusty, dwarf and stem. Smut reduces grain yield by 20-30%. Plants are infected during germination and during the growing season. Fungi destroy the affected parts of plants, they form a lot of spores in the form of a powdery, sometimes unpleasantly smelling mass.

Powdery mildew

The fungus infects the aerial parts of wheat, manifests itself in the form of a soft thin coating, first white, then acquiring a gray or yellowish color. Over time, the plaque thickens, black dots of spores are visible in it.

In diseased specimens, the assimilation surface of the leaves decreases, chlorophyll and pigments are destroyed, with a strong infection, bushiness decreases, heading slows down, grain ripening accelerates, but it is sometimes defective. The shortfall in the wheat harvest can be in the range of 10-15%.

Leaf spot

The main leaf disease of the crop. The pathogen infects leaves, stems, grains. Symptoms appear on seedlings and adult plants, these are small yellow-brown spots that increase over time, then coalesce, turn yellow and necrotic.Chlorotic spots are also noted.

Brown and brownish chlorosis spots form on stems. Leaf spotting can be determined by brown scales on grains, a pinkish tint of seeds.

The harmfulness of the disease is expressed in the early drying of wheat leaves, the frailty of the grain, the shortening of the ear and the number of grains in it. Losses can reach 60%.

Fusariosis spike

This wheat disease results in a significant reduction in yield and deterioration in grain quality. Infected seeds germinate slowly, sprout poorly. The infected grain looks skinny, wrinkled, with a matte, slightly pink surface, a whitish coating can be seen in the groove, a dark embryo.

Infected wheat grain contains fungal toxins, therefore it is unsuitable for processing and feed for livestock and poultry. When eating it, severe poisoning, damage to the liver and kidneys, and organs of the reproductive system are often possible.

Ergot

The spread of the disease is facilitated by wet, cold, windy weather, infection occurs during flowering. The initial signs of the disease appear after the ear emerges, it is a sticky liquid that attracts insects that carry spores. In places where the pathogen penetrates, sclerotia-horns are formed, at first they are yellowish, when ripe they become gray-violet or black-violet. The horns crumble to the ground or remain in the grain after harvesting; when threshed, they spoil the quality of the grain, which becomes poisonous.

Rot

Root rot of wheat - fusarium, helminthosporium, ophiodisease, cercospollereznaya. Rots lead to a significant decrease in yield, diseases can lead to loss of seedlings, a decrease in bushiness, weight of grains, their quantity, and a decrease in their quality.Losses from wheat rot can result in a 15-40% reduction in expected yield.

Bacterial diseases

Their pathogens are bacteria of different types. They affect various organs of plants, but lead to the same result as fungal diseases - a deterioration in the condition of plants, the quality and quantity of grain.

Bacteriosis striped (black film)

Black bacteriosis affects the whole plant, all its parts, but more often develops on the ear. The onset of the disease usually occurs in the tillering phase, the symptoms are watery greenish spots that cover the leaves, then they become yellowish-brown, chlorotic. In the advanced phase of the disease, the spots remain yellow, so they are almost invisible on drying leaves.

When wheat is heavily infected, browning spreads to the ear, which decreases, deforms, the grain becomes frail. Often the ear is underdeveloped.

Bacteriosis basalis

Manifested in the defeat of the scales of grains and various parts of plants. At the beginning of the disease, the foliage is covered with oily transparent yellowish or whitish spots. Then they lengthen, turn brown and dry out. With severe infection, browning affects the awns and the stem of the ear, which is deformed. The grain also turns brown, becomes skinny.

Bacteriosis yellow (mucoid)

Infection of seedlings is expressed in the appearance of longitudinal discoloration on the veins and along the edges of the leaf. Mucus appears on the affected tissues, with severe damage, the foliage dries up and dies or twists, becomes folded and slimy. The ear turns yellow and twists, the grains do not develop.

Striped wheat mosaic

Caused by a virus carried by gall-forming mites. During the tillering period, a yellowish or chlorotic streaked spot is formed between the leaf veins.As the mosaic progresses, the strokes are transformed into large longitudinal stripes. Wheat infected in the early stages is not capable of tillering and heading.

Crop pests

Pests do no less harm than diseases. They oppress plants and reduce their productivity.

Wheat thrips

Wheat is harmed by larvae and adult insects. Imagoes damage scales, awns, flower films, suck out the juice, due to the lack of which the output of the ear is delayed, the grain becomes feeble. The larvae damage the pouring grain, reducing its weight and quality.

Grass aphids

Insects live on stems, leaves. Aphids on plants in the phase of emergence into the tube can lead to their death. In plants affected by pests, the quality of the grain deteriorates, which becomes frail, the ear is empty. Aphids carry viruses, food sites become discolored or red.

Grey Grain Scoop

Larvae of different ages harm wheat, they destroy the ovary, feed inside the grains, eating them completely. If the grain is already sufficiently developed, they gnaw cavities in it from the outside.

Bug harmful turtle

Imagoes and larvae older than the second age harm plants. Adults feed on juice, a constriction forms on the stem at the puncture site, the stems do not wither, but they do not develop and gradually die off.

The larvae do the most harm, they feed on the grain of the early stages of development. Seeds shrivel and do not develop. Bedbug-damaged grain flour of poor quality.

Sawflies

The larvae harm, damaging the stems, eating holes in it. Damage to vascular tissues leads to drying of the ear, grain frailty. Losses also occur during harvesting, as the plants lie down and break off.

Nematodes

Signs of nematode damage on young plants - waviness and curly foliage, developmental delay, shortening of internodes. On adult plants, the leaves curl, the ear is greatly shortened, and the duration of ripening increases. Yield losses can be 30-70%. Simultaneously with the pest, dilophosporosis often develops.

White grub grubs

The pest develops in humus-rich soil. Signs of damage are oblong or rounded cavities on the stem. Harmful microorganisms often penetrate damaged areas.

Wireworms

The larvae gnaw out passages in plants, penetrate into the roots. Can damage sown seeds, seedlings. Harm is expressed in the loss of part of the plants, the oppression of the rest.

Hessian fly

The larvae harm seedlings, weaken them and lead to death. On older plants, stems are damaged in the zone of nodes. Plots slow down growth and break off, the ear may not form.

Resistant wheat varieties

One of the effective methods of combating wheat diseases and pests is the cultivation of varieties that are resistant to certain infections and insects. Universal varieties that would be resistant to many diseases have not been bred, the choice of varieties is dictated by the prevalence of pests or diseases in the growing area.

Modern sustainable crop varieties: Yuzhanka, Stavka, Kuren, Berezit, Grom, Astarte, Euclid, Tacitus, Vekha, Solokha, Karolina and others.

A large percentage of the wheat crop is lost every year due to fungal and bacterial diseases. One of the main tasks facing farmers is the fight against diseases and pests of crops, expressed in the use of pesticides, crop rotation and proper storage of grain.

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