[Symptoms] The term “drug injury†refers to the improper application of pesticides, which results in obstruction of the normal physiological functions or growth of the protected crop or damage to a series of abnormal phenomena. There are two kinds of acute and chronic injury. Acute symptoms develop rapidly within a few hours to 3-4 days after spraying. Such as burns, withering, falling leaves, falling flowers, fruit drop. Chronic phytotoxicity is caused by obvious reaction after spraying for a long time, due to inhibition of physiological activities, poor performance of growth, abnormal leaves, delayed ripening, deterioration of flavor, dissatisfaction of grain, etc. Symptoms of the leaves are obvious and common, such as the appearance of colorful spots, local tissue scorch, perforation or shedding, or yellowing of the leaves, chlorosis, thickening deformity.
ã€Causes】 pesticide sprayed on the leaves, mostly from the pores, water holes, wounds infiltration, and some can also penetrate from the branches, leaves, flowers and root epidermis. When the application is improper, the particles of the agent directly obstruct the stomata and pores in the leaf surface, or enter the tissue and block the intercellular space, causing the normal respiration, transpiration, and assimilation of the crop to be inhibited; after the agent enters the plant tissue or cells, some The chemical reaction of the substance causes the normal physiological function to be destroyed and abnormal symptoms and physiological abnormalities occur.
[Control methods] Select pesticides that are safer for crops. Try to avoid spraying when the crop is weak in drug resistance. General seedling stage, flowering fruit setting period is most likely to produce phytotoxicity, and special attention is required. Correctly grasp the application techniques, strictly follow the prescribed concentration and dosage, and mix scientifically and rationally. Avoid spraying at hot noon. Because under high light and high temperature, the resistance of crops is weakened, the activity of pharmaceuticals is enhanced, and it is easy to produce phytotoxicity. Take remedial measures, seed buds, seedlings minor damage, through strengthening management, appropriate nitrogen fertilizer application, to promote the early growth of seedlings into normal growth. Leaf or plant damage is heavy, should be timely irrigation, increase phosphorus and potassium fertilizers, cultivating root development, enhance recovery. If you spray the wrong agent, you can spray a lot of clean water, and pay attention to irrigation.
Watermelon medicine prevention and treatment methods
Now it is a small shed, and mulching watermelon growth and development, plant water content is high, are sensitive to a variety of chemicals, once the application of excessive concentration or improper use of drugs, it is prone to phytotoxicity. The remedial measures after the occurrence of phytotoxicity of watermelon are:
1. Rinse with water. Most chemicals are not resistant to water erosion. If the pesticide concentration is too high due to excessive application concentration, sprayers can be filled with fresh water immediately (preferably within 6 hours after application). Spray the stems and leaves repeatedly to wash away residuals. The agent on the surface of the plant reduces the harm of the pesticide. When flushing, the pressure of the sprayer should be sufficient and the amount of water sprayed should be large.
2. Use poison to attack poison. Potassium permanganate is a strong oxidant and has oxidation and decomposition effects on various chemical substances. According to tests, in the case of phytotoxicity or the discovery of medication in watermelon, spraying potassium permanganate 5000 to 7000 times immediately, can ease the phytotoxicity.
3. Suspension of medication. Before the phytotoxicity has not been completely relieved, minimize the use of chemical pesticides, especially similar pesticides, and stop using them so as not to aggravate phytotoxicity.
4. Strengthen management. After the phytotoxicity of the watermelon, combined with watering appropriate to add some of the available fertilizer, and then cultivating the loose soil, can promote the plant as soon as possible to restore normal growth and development.
In addition, it can also be combined with root fertilization and watering, foliar spray phosphorus, potassium, in order to improve plant nutrition, enhance root absorption capacity. The method is: to superfine calcium superphosphate 1 kg, add water 40 ~ 50 kg, soak a day and night, take the supernatant sprayed watermelon stems and leaves, or with the harvest No. 1000 times liquid spray and 800 Irrigation; plus 0.2-0.3% potassium dihydrogen phosphate solution sprayed 50 kg per acre; root sprayed 1.8% love more than 6000 times liquid, (or a sprayer against half a bag) is also conducive to plant normal growth and development.
For the production and management of watermelon should be cautious, watermelon sensitive to carbaryl, do not use the drug in watermelon, watermelon is a chlorine crop, pay attention to when using fertilizer and medication do not use chlorine-containing drugs, fertilizer, etc., so as not to cause drug damage The damage affects the normal growth of the watermelon.
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