Description and treatment of diseases and pests of corn, measures to combat them

Diseases of corn can be caused by viruses, bacteria and very often fungi. The quality and quantity of the crop is sharply reduced. If measures to combat them are not taken in time, then diseases can lead to a complete loss of the crop. Knowing the first signs of a problem, you can stop the further spread of the infection.

Diseases of corn, photos, their signs, control measures

Corn is a cereal crop. If a crops of corn will be susceptible to diseases and pests, then it will not work to get a good harvest. In order to prevent the appearance of infection, as well as its spread, you need to be able to recognize the first signs of a problem and take action in time.

Infection with diseases occurs due to poor-quality planting material, improper crop care, and untimely pest control. Therefore, it is so important to establish an irrigation regime, apply fertilizers on time in order to form a good immunity and observe other agricultural practices.

Dusty smut

The fungal disease dust smut affects the panicle and ear of corn. This is a common disease in the humid regions of the southern regions (Kuban, Transcaucasia). Diseased plants look weak, grow poorly, tiller strongly, cobs are poorly formed. Gradually, the affected ears turn black, become covered with spores and turn into a dusty mass.

The cause of the onset of the disease is contaminated soil, poorly processed seeds, high air temperature. The main measure of the fight against dust smut and bladder mildew is the pickling of seed material before sowing, compliance with the annual crop rotation. Should choose varieties and hybrids of corn resistant to these fungal diseases.

If diseased plants are found in the garden, they must be destroyed (it is better to burn or bury them to a depth of about 50 cm). It is recommended to plant corn on a new plot of land every three years.

Bubble smut

The causative agent of corn blister smut is a fungus that affects the entire aerial part of the plant. Small pink or greenish bumps appear in the affected areas. Over time, the swelling grows and becomes black in color. Soon, the bladder membrane ruptures, and spores, with the help of wind and insects, fall on other, healthy plants.

Infected plants, untreated, infected seeds become the source of infection. The bladder smut is especially harmful when a stalk and cob appear on the internodes. In this case, the grain yield is reduced to 50%.Drought and late sowing of plant seeds provoke the disease.

The main preventive measures are considered to be the choice of varieties and hybrids of corn that are resistant to blister smut, pickling of planting material, cleaning of plant residues from the site after harvesting, compliance with crop rotation. Seed collection is carried out only from healthy plants.

Effective drugs for blister smut, as well as for root and stem rot, are: Alfa Treater, Delit Pro, Vincent, Lanta, Pioneer, Maxim XL.

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Fusarium

Fusarium maize can appear at any stage of plant development. The causative agents of the disease are fungal spores that are in swellings. The disease leads to rot of seeds, roots and stems, as well as the ears. Accordingly, the symptoms will differ.

Rotting seeds and seedlings occurs as a result of sowing contaminated planting material. Most of the seeds rots already in the soil, without forming the first shoots. A light or pinkish bloom forms on their surface. Young plants grown from infected seeds on the surface of the earth look weak, stunted and poorly forming cobs.

In the phase of milky-wax maturity, stem and root rot often appears. The leaves of the plant wither, turn yellow, dry out. The roots turn black, dry out and the affected corn can be easily pulled out of the ground. The cobs themselves gradually dry up and wither.

Corn rot may appear even during the storage period of the harvested crop. First, a white-pink bloom appears on the grains, gradually the entire ear is affected. The color of the plaque darkens and becomes brownish gray.

The source of infection is contaminated seeds or unharvested plant debris on the land. Wet, cold weather, high air temperature during the ripening of the ears, damage to the ears and grains by pests can provoke the disease.

Before planting, it is imperative to pickle seeds, choose varieties and hybrids of corn that are resistant to fusarium, and detect and remove diseased plants in time. Shown is the autumn plowing of the land and the harvesting of plant residues, timely control of insect pests.

Stem rot

A fungal disease of stem rot manifests itself at the end of the growing season at the stage of milk maturity of corn. The description of this maize ailment is as follows: the leaves become gray-green and covered with a matte bloom, dry out, wither. A pinkish bloom can be observed on the stem, over time it softens and breaks.

The source of infection is the persistence of spores in plant residues after harvest. The fungus actively reproduces in hot, dry weather. Incorrect watering and too thick sowing of corn becomes a provoking factor.

To increase the resistance of plants to rot, it is necessary to observe the optimal sowing time, planting density and depth of planting seeds, after harvesting, you need to dig up the site and remove all plant residues, it is imperative to pickle the planting material with fungicides.

Southern helminthosporiosis

Most often, the leaves of the plant, less often the roots and the cob, suffer from the southern helminthosporiosis of corn. The first signs of the disease are the appearance of brown oblong spots on the leaves. Gradually, the affected area dries out. The spots grow and occupy the entire leaf area.

Spot or helminthosporiosis of corn appears in mid-summer. High humidity and low air temperature become a provoking factor. The source of the spread of infection is untreated seeds and plant debris.

Before planting, be sure to sort and pickle the seeds. When infected seeds are planted, the seedlings are weak and often unable to reach the soil surface.To increase immunity, fertilizers are applied to the soil several times per season. It is undesirable to plant corn for three years in a row on the same plot.

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Maize pests, their signs and control measures

Insect pests are considered one of the reasons for the spread of diseases among cereals. To combat them, you can use both folk remedies and ready-made preparations.

Stem moth

Maize pests eat the ground and underground parts of the plant, as a result, it weakens and becomes susceptible to disease. In addition, the pests themselves can transfer pathogenic bacteria from a sick plant to a healthy plant.

More harm to the plant is brought not by adults, but by the caterpillars of the moth. Gray-yellow caterpillars (25 mm long) are especially active in July-August, when the weather is dry and warm. Caterpillars of the corn stalk moth live on the surface of plants, penetrate the petioles of the stems, leaves and flowers of panicles.

Plant nutrition is disrupted, sometimes the stems can break. The plant begins to bloom later, the size of the leaves decreases, pollination worsens.

In order to prevent the spread of the meadow moth on corn, it is necessary to combat weeds, mow them around the plantings, and do not leave the tops after harvesting.

Root aphid

Root aphids most commonly attack corn in hot, dry weather. The plant slows down in growth, the leaves turn yellow and dry out, it is easily affected by fungal diseases. If the area of ​​infection is small, then diseased plants can be cut off.

Insecticides and fungicides are used to protect plants from pests (Konfidor, Aktellik, Fitoverm, Fas). Since insects can overwinter on the remains of the stems, after harvesting, you need to clear the site of all vegetation. It is best to choose early maturing corn varieties.

Swedish fly

The Swedish fly most often infects corn during the germination period. The larvae damage young seedlings, and they begin to lag behind in growth and development. The leaves of the affected corn turn dark green and the stem thickens. Corn pests reduce not only the quantity of the crop, but also its quality.

During the mass summer of flies and egg laying, it is recommended to treat the plants with such preparations as Karate, Decis, Tsiperon. As a preventive measure, it is useful to feed with nitrogen fertilizers, observe the optimal sowing time and select resistant varieties of corn.

Preventive measures

Prevention should begin from the moment the seeds are selected and end with clearing the field from plant residues. Preventive measures:

• It is better to choose early maturing corn varieties.
• It is advisable to pickle the seeds.
• When planting, it is recommended to add potassium-phosphorus fertilizers to the soil.
• It is important to know the first signs of the appearance of diseases and pests.
• Remove damaged plants from the site in time.
• Dig deep into the field in the fall.

Another common corn disease is bacterial wilting or wilt. The bacterium infects all organs of the plant. Light green and yellow stripes appear on the leaves.

The main control measure for the disease is to avoid sowing infected seeds. In addition, the grains need to be treated before planting, to get rid of pests in time and to fight weeds.