What kind of medicine is used in tobacco climate spots?

Tobacco climatic spot is a physiological disease mainly caused by ozone and nitrogen compounds in the air, and it is one of the main tobacco diseases in the world. So what kind of medicine is used for tobacco climate spots?

What kind of drugs are used in tobacco climatic spots

Climatic spot is a physiological disease, common fungicides are ineffective to the disease, but some protective fungicides can be used in production. When there are sporadic symptoms in the field, potassium dihydrogen phosphate or Bordeaux solution can be sprayed on the leaf from the cluster stage, or 500-fold solution of Dysen zinc or 700-fold solution of thiophanate methyl.

Second, the cause of the disease

1. Varieties: the large area occurrence of tobacco climatic spot is related to the relatively susceptible varieties planted all the year round. Yunyan 87, Yunyan 97 and K326 have weak resistance, which is also an important reason for the epidemic of tobacco climatic spot.

two。 Flue-cured tobacco transplanting period: long-term low temperature and sunny weather, can not grow early and quickly after transplanting, tobacco seedlings grow differently, tobacco plants are tender and weak, stress resistance is poor, and they are susceptible to disease.

3. Rainfall: large-scale rainfall caused tobacco root growth hindered, tobacco field nutrition loss, the formation of tobacco field microclimate environment conducive to the outbreak of climatic spot disease.

4. Cold air: cold air attacks can lead to an incidence of climate spot disease of about 40%, with an area of more than 200 hm2. To sum up, in the susceptible stage, there are more precipitation days, less sunshine hours, increased field humidity and suitable temperature, which fully meet the needs of meteorological conditions for the occurrence and prevalence of climatic spots, thus increasing the occurrence and harm of the disease.

III. Prevention and control methods

1. Selection of disease-resistant varieties: a number of disease-resistant or disease-resistant varieties have been cultivated and introduced in China, and have been demonstrated and popularized in different stages and regions, among which Yunyan 97, Honghua Dajinyuan, NC89 and Cuibi No.1 have better disease resistance.

two。 Do a good job in cultivation management: as climatic spot disease mainly occurs in the lower and middle leaves, effective cultivation and management measures include the following aspects: first, 2 foot leaves and 3 lower leaves are not suitable for tobacco, so as to effectively improve the field microclimate, reduce soil moisture and reduce the occurrence of the disease; second, ploughing and cultivating soil to achieve loose soil, promote tobacco root growth and improve tobacco stress resistance. The third is to keep the field clean and free of weeds and improve the interrow permeability.

3. Water and fertilizer management: fertilizing according to the fertilization principle of controlling nitrogen fertilizer and increasing phosphorus and potassium fertilizer, avoiding the sudden growth of tobacco plants, achieving a stable ratio of nitrogen, phosphorus and potassium during fertilization, and at the same time increasing the application of organic fertilizer and farm manure to improve the soil properties of tobacco fields to improve the resistance of tobacco plants.

Climate spot disease is unavoidable, if it occurs, it will cause a greater impact, so it can only be prevented and treated daily.