How to prevent and cure tobacco red spot? What are the other diseases?

Tobacco is widely cultivated in the north and south provinces of China. In addition to making tobacco products for people to smoke, tobacco can also be used for medical treatment and killing "four pests" (snails, mosquitoes, flies, rats) and insects. So, how to prevent and cure tobacco red spot? What are the other diseases?

First, how to prevent and cure tobacco red spot?

1. Which parts are mainly harmed?

Red spot is one of the main diseases of tobacco, which mainly harms leaves, stems, pedicels and capsules. It occurs seriously in Shandong, Henan, Anhui, Heilongjiang and Jilin, followed by Sichuan, Yunnan, Guizhou, Liaoning, Shaanxi and other tobacco areas.

2. When will the disease occur?

Alternaria alternata begins to produce conidia when the temperature reaches 7-8 °C and the relative humidity is greater than 50% in the following spring, and spreads from air, wind and rain to the tobacco plants in the field and infects the lower leaves (primary infection). These infected tobacco plants produce conidia on the disease spots and are transmitted by wind and rain to form re-infection; after repeated re-infection, the pathogen can infect any part of pedicels, capsules, lateral branches and stems.

3. What are the symptoms?

Leaf infection occurs mostly from the lower leaves, gradually developing upward, beginning with small yellow-brown spots, and later developing into brown round or near-round spots, which are brittle and fragile, and seriously make the leaves become broken leaves; leaf veins, pedicels, capsules, stems infected with long oval or fusiform dark brown sunken spots.

4. What are the methods of prevention and control?

(1) Agricultural prevention: first, plant tobacco varieties that are more resistant to brown spot; second, increase the application of organic fertilizer to improve the disease resistance of tobacco plants; third, plant density should not be too high, so as to avoid rapid epidemic after the occurrence of the disease; fourth, do a good job in field hygiene. the bottom leaves, branches and stems should be taken out of the field for deep burial or sun-drying and destroyed; fifth, the rotation system should be implemented for more than two years.

(2) Pharmaceutical prevention: when the bottom leaves were harvested for the first time, 400 × 500 times of 40% sclerotia net wettable powder was sprayed every 10 days for 2 times in a row; at budding stage, 1.5% more than 100 times of antimycin was sprayed on the leaves, and it was applied again half a month later.

(3) Drug treatment: at the initial stage of the disease, spray 10% Polaroid wettable powder 800 times 1000 times, once every 7 days for 2 times, or spray with 30% acrylic suspension 600 times 800 times, 47% Baofengning wettable powder 600 times 900 times, once every 7 days, a total of 2 times 3 times.

What are the other diseases of tobacco?

Other tobacco diseases include mosaic, bacterial wilt, black stem, anthracnose, powdery mildew, wildfire, angular spot, coal fouling, catchment, downy mildew, Sclerotinia sclerotiorum, white silk, black spot, frog eye and so on.

1. Mosaic disease: it is mainly transmitted through contact, but aphids can also infect some varieties. Not paying attention to sanitary operation is the key to the pandemic of mosaic disease. At present, there is no single treatment method for mosaic disease, mainly to prevent mosaic disease; reasonable crop rotation, good field hygiene, emphasis on sanitary operation, prevention and control of aphids, and apply virus clearance, poison elimination, fungicide and other medicament prevention before the virus enters.

2. Bacterial wilt: the main sources of primary infection are pathogens in soil, diseased and residual tissues and fertilizers, and running water in diseased fields is the most important way for disease re-infection and transmission; disease-resistant varieties can be selected, disinfection can be done well, rotation for more than 3 years, high ridges, drainage and irrigation, no retting fertilizer of diseased plants is needed, and quicklime is used to disinfect disease holes after discovering diseased plants in time.

3. Black stem disease: soil is the main source of infection, followed by compost made from the remnants of diseased plants, and the main transmission medium is surface running water; disease-resistant varieties can be selected, rotation for more than 3 years, high ridges, irrigation and irrigation. When sporadic disease occurs, the leaves are sprayed with 600-fold solution of 30% carbendazim, and the diseased stems and leaves should be removed, burned or buried in time.

4. Angular spot disease: the pathogen overwinters on diseased bodies or seeds, can also survive near the roots of some crops and weeds, and becomes the initial infection source of the disease the following year, and the pathogen is mainly transmitted by wind, rain and insects; seeds should be disinfected, seedbeds should also be disinfected, timely ventilation and dehumidification, weeding seedlings, drainage and humidification, rotation for 2 ~ 3 years, disinfection leaves or diseased plants should be removed and 200 units of agricultural streptomyces should be sprayed.

5. White silk disease: the pathogen overwintered in the soil as sclerotia or mycelium, and often spread with soil, organic fertilizer and irrigation water; more than 3 years rotation, compost made by enzyme bacteria retting or mature bio-organic fertilizer, plant ash was applied in the middle and later stage of growth, and 1000 times of carbendazim wettable powder was sprayed at the base of the stem in the early stage of the disease.

The above is the introduction of the control methods of tobacco red spot and other diseases. I hope it will be useful to you.