What pesticides are used for tobacco anthracnose

Tobacco anthracnose is caused by fungi of the genus Alternaria. The disease can occur in all growth stages of tobacco, but it is common and serious in seedling stage. The leaves of seedlings are covered with disease spots, which often destroy the whole tobacco seedling when the disease is serious. So what kind of pesticide is used in tobacco anthracnose?

What pesticides are used in tobacco anthrax?

The commonly used agents of tobacco anthracnose are: copper sulfate, silver nitrate, formalin, chlorothalonil, mancozeb, anthrax Fumei, Bink, carbendazim, carbendazim, carbendazim.

Second, symptoms

Leaf infection: dark green watery spot at first, and then expand into brown round spot, the spot is slightly sunken in the center, white to yellow-brown, the edge is obvious, slightly raised, brown. There are wheel lines and small black spots on the disease spot when it is wet. When dry, the disease tissue is old and hard, and the disease spots are mostly yellow or white, without wheel lines and black spots. When the disease is serious, the disease spot fuses into large spot, which makes the tobacco leaf shrink or scorch.

Leaf veins, petioles and young stems are infected: the spot is fusiform, brown, sunken and longitudinally cracked, and when the seedling is seriously broken, the petiole is broken. In the adult stage, most of the disease occurred from the lower leaves and gradually spread upward.

Stem infection: the disease spot is large, forming longitudinal fissure reticular spots, depression, dark brown, when the climate is humid, the disease grows into black spots. Sepals, capsules infected with brown suborbicular spots.

III. Prevention and control methods

1. Select a good seedbed, carry out film breeding, breed and plant disease-resistant varieties according to local conditions.

two。 Select disease-free seeds or seeds for disinfection, and use seeds on disease-free plants. For seed disinfection, generally soak the seeds with 1% copper sulfate or 0.1% silver nitrate or 2% formalin solution for 10 minutes, then rinse the solution thoroughly with clean water, and then accelerate germination or dry sowing seeds. Seeds can also be mixed with 15% of the seed weight of 0.2% vermicelli.

3. Nursery bed management: choose non-continuous cropping land with high dryness, good drainage and fertile soil as seedbed, grow away from stubble land, vegetable garden, roasting house and tobacco shed, and use plastic film to cover seedlings. Reasonable close planting, pay attention to ventilation in the field; the seedling bed is required to be flat, carry out "double bottom" or "three bottom" before sowing, do not water the seedling bed as far as possible, and choose sunny morning to avoid flood irrigation. The disease resistance of the plant was improved by applying rotten fertilizer and increasing phosphorus and potassium fertilizer.

4. Strengthen the cultivation management and pay attention to the application of bacteria-carrying fertilizer. The surface of the tobacco border should be flat and make a good drainage ditch to prevent the accumulation of water in the border after rain. Sowing density should be suitable, not too dense, early seedlings, sparse seedlings, to promote the strong growth of seedlings and improve disease resistance. Small water irrigation should be used frequently after tobacco seedlings are unearthed to prevent flood irrigation.

Tobacco anthracnose is easy to be confused with climatic spot disease. The similarity between the two is that they both produce small brown spots on the leaves of tobacco plants, so they must be carefully identified and the right medicine will be effective.