Tobacco is considered a fairly common crop, the cultivation of which has a number of features. For it to be successful, it is important to strictly adhere to basic agrotechnical recommendations. At the same time, sometimes the process is accompanied by various kinds of problems. Among them, it is worth highlighting the development of diseases and pest attacks. To cope with the problems, it is important to identify the causes of tobacco diseases and take measures to eliminate them.
Black root rot
In most cases, this disease affects seedlings, but sometimes adult crops are also affected. Leaves on diseased bushes wither, turn yellow and dry out. In this case, the roots become black and often die. In mature plants, the foliage withers and black and white spots appear at the ends of the roots.
The cause of the disease is a fungal infection. It often provokes the death of seedlings. When planting it in open ground, there is a risk of thinning the plantation.
Blackleg, or seedling rot
Tobacco is highly susceptible to this disease. As it develops, darkening and thinning of the base and then most of the stem are observed. As a result, damaged bushes die. Most often, the pathology spreads in patches. However, sometimes the entire seedling suffers. The cause of the disease is fungi.
With diseased seedlings, the disease can enter the plantations and cause their thinning. The pathology is most manifested by high air humidity, excessive fertilizing and thickening of plantings.
Dry root rot
Young bushes are more affected by this disease. The pathology is accompanied by wilting of foliage and thinning of the roots. As a result, the entire bush dies. The causative agent of the disease is considered to be the lower fungus Olpidium nicotianae Preiss. When bushes are infected, significant thinning of plantings in greenhouses is observed.
Powdery mildew
This pathology is accompanied by the formation of a white powdery coating on the bushes. First, it covers individual areas, and then the entire surface of the leaves. The lower foliage is the first to suffer.
The causative agent of the pathology is considered to be a marsupial fungus. It can accumulate in weeds and spread to crops. Pathology leads to a noticeable decrease in the grade of tobacco.The fact is that damaged foliage becomes brown during drying and loses its taste.
Downy mildew, or downy mildew
This is the most common tobacco disease. As it develops, the leaves and cotyledons of the sprouts become covered with yellow-green spots. After which the edges of the foliage curl down. In the area where the spots are located on the bottom, and sometimes on top, of the leaves, a gray-violet coating forms.
With increased air humidity, the affected foliage fragments darken and become oily. The plant quickly withers. With the rapid development of pathology, the seedlings die in 3-4 days. This process is accompanied by an unpleasant odor.
In field conditions, downy mildew is characterized by the formation of chlorotic spots on the foliage. Moreover, their shape and size are determined by weather conditions and varietal characteristics. Most often, the spots are round in shape and limited to the veins of the leaves.
Brown dry spot, or Alternaria
This pathology most often develops in the second half of summer. In this case, the foliage becomes covered with large round spots of a brown hue. They are covered with a dark velvety coating.
The causative agent of brown dry spotting is considered to be a fungal infection. In areas of plaque, conidiophores with conidia are formed. The risk of pathology increases during periods of precipitation and can lead to serious losses in foliage and seed yields.
Bacterial grouse
If the leaves are infected with bacteria, sharply defined spots of various shapes appear on them.After some time, their sizes increase and merge with each other. The spots are white or brown in color. In this case, the affected areas fall out. They leave holes behind.
Tobacco grouse is most pronounced in early summer. The disease is not contagious. In this case, bushes that grow in open areas suffer the most. The risk of developing the disease increases with low soil fertility and sharp temperature fluctuations.
Tobacco or ordinary mosaic
This pathology is characterized by the formation of light green spots that alternate with the normal greenness of the leaf. With a seed infection, yellowing of the veins on young foliage is observed. In this case, the plates become covered with specks. The edges of the youngest foliage curl slightly upward, forming a rim. After this, large bubble-like swellings form on them. Sometimes the leaves become thread-like.
Cucumber mosaic
This type of mosaic is accompanied by the formation of spots on the plant. In this case, the bushes become covered with dark green blisters, and the ends of the leaves dry out.
The causative agent of the disease can hide in cucumbers, tomatoes or pumpkin for a long time. The cucumber mosaic is spread by the peach aphid. That is why it is so important to take measures to combat it.
Bronzing, or apical chlorosis
External signs of pathology depend on the affected area of the crop. The most famous sign is the formation of a pattern on the leaf blades. It forms lines, circles or weaves. Young plants that are affected by bronzing usually die. Thrips are considered carriers of pathology. This is why it is so important to combat these pests.
White moth
This pathology is characterized by the formation of small necrotic spots of various shapes.They can be 2-10 millimeters in diameter and have pronounced zoning. Later, the spots acquire a lighter color, and the zonality disappears.
The viral infection is inactivated by drying the foliage. The pathology is spread by peach aphids. In this case, the infection may remain in the seeds.
Plant pests
Common pests of tobacco include:
- mole crickets;
- field slugs;
- tobacco thrips;
- aphid.
Tobacco suffers from many diseases and harmful insects. To cope with them, it is important to identify the causes of problems in time.
