Fungal diseases of cereal crops are widespread. Favorable regions for the spread of wheat septoria are with a moderately mild and humid climate. Let's consider the causes and symptoms of the disease, how to determine the disease by the appearance of plants, how harmful the pathogen and the disease are. Preparations and methods of treatment of septoria and preventive measures.
Causes and symptoms of the disease
Septoria causes the greatest harm in the Central region of Russia.The disease negatively affects the development of cereals, the assimilation surface of the leaves decreases, the ear develops poorly, and the grains ripen prematurely. Winter and spring wheat crops bush more intensively, the ears grow short, with a small number of grains. The shortfall in yield can be up to a third of what healthy plants can produce.
The causative agent of septoria is a fungus of the species Septoria tritici. The mycelium affects the leaves and stems of cereals and is characterized by the formation of spots, initially light yellow and brownish in color with dark edges and black spots of spores. Affected leaves lighten, lose their green color and begin to dry out. The stems turn brown, wrinkle and bend, and almost no spores are formed on them.
Septoria tritici affects only wheat among cereals. The fungus enters plants from residues - stubble and straw that remain in the field, infected cereal grasses and seeds. Diseased seeds produce diseased plants. Spores spread most strongly in the presence of fog and precipitation.
They germinate in droplets of moisture at a temperature of 9-28 °C. They develop most quickly at 20-22 °C. Spores are able to germinate at air humidity above 76%. The incubation period lasts 6-9 days. During the growing season of wheat, several generations of fungi can develop. In hot, dry air, spores can be viable for 3 months or more.
Early winter and late spring crops are more affected by septoria than those sown on time. When mineral fertilizers with basic elements are applied, plants become more resistant to disease; the application of nitrogen alone reduces resistance.
Harmfulness of the pathogen
On leaves affected by septoria, due to fungal spots, the photosynthetic area decreases, and therefore the synthesis of useful substances decreases. In diseased plants, the number of grains and their weight in the ear decreases. Darkening of the embryo may be observed. Septoria leads to crop shortages and causes economic losses to enterprises.
How to get rid of septoria
Fungal spores can be destroyed by treating the seeds before sowing; the drugs protect wheat during sowing and germination from pathogens that are on the surface of the grains and in the soil. The disinfectants used are “Shooting Range”, “Attic”, “Armor 3”, “Dividend Extreme”.
If signs of the disease are detected, the crops are treated with Alto Super, Amistar Trio, Titan, Abacus, Tsimus Progress, and Impact Exclusive. Biological pesticides “Rizoplan”, “Glyokladin”, “Alirin-B” are also used. If the fungus is found on the developing grain, then it is necessary to carry out treatment at the heading-flowering stage.
Prevention measures
The appearance of septoria blight on wheat crops can be prevented by using healthy seeds or those treated with a disinfectant. Sow seeds at the right time, not too early and not too late. Observe crop rotation, sow wheat after predecessors, on the remains of which fungal spores cannot remain.
To prevent seed contamination by fungus, you need to harvest the grain on time and dry it.In the fall, it is necessary to peel the stubble and plow the soil deeply to destroy as much plant debris as possible infected with fungi.
Wheat septoria affects the leaf blades of cereals, which worsens the condition of the plants. Spikelets, grain and, ultimately, the harvest suffer. The shortage of grain can be up to a third of the planned harvest. The disease spreads in warm, humid weather; spores require droplet or air moisture for germination. Heat and dry air stop the development of the pathogen.
