The phytotoxicity refers to a variety of morbidity reactions caused by improper application of pesticides, including a series of abnormal physiological changes such as tissue damage, growth inhibition, plant metamorphosis, and reduced yield. In the process of prevention and control of pests and diseases of vegetables in protected areas, due to the special climatic conditions of protected areas, phytotoxicity can easily occur and cause unnecessary losses. The causes, symptoms and remedial measures for the damage caused by the vegetables in the protected areas are described below for reference. First, the cause of the first is misuse of pesticides or misuse of herbicides, the second is the application of pesticide concentration is too large or continuous repeated application, the third is the application of high temperature or high humidity conditions, the fourth is the use of inferior Pesticides, the fifth is the soil application is not uniform enough. Second, drug injury symptoms 1. Spots: Spots mainly occur on the leaves, and sometimes also on the stems or fruit epidermis. Brown spots, yellow spots, and net spots are common. The spots caused by phytotoxicity are different from those caused by physiological diseases. There are no regular patterns in the plants. The entire site is light and heavy, while the lesions are usually widespread, and the sites where the symptoms appear are more consistent. Compared with the spots caused by fungal diseases, the size and shape of the spot caused by phytotoxicity vary greatly, and there is no disease center. 2. Yellowing: Yellowing occurs mainly in the stems and leaves of vegetables, mostly in leaves. The main cause of yellowing is the destruction of chlorophyll in the leaves by the pesticides, yellowing of the light leaves, and yellowing of the whole plants. 3. Malformation: Abnormalities caused by phytotoxicity can occur in stems, leaves, fruits, and roots of vegetables. Commonly there are leaf curling, clumping, rooting, and fruit deformities. The malformations caused by drug injury are different from those caused by viral diseases. The former occurs universally, and the plants show local symptoms. The latter often occur sporadically, manifesting as systemic symptoms and often accompanied by symptoms such as mosaic leaves and wrinkled leaves. 4. Wither: The wilting caused by phytotoxicity is often a symptom of the whole plant, which is generally caused by improper application of herbicides. The wilt caused by drug injury is different from the wilt symptom caused by plant disease. The former has no disease center, and the process is relatively slow. After the first yellowing, the seedlings are killed and the transducing tissue is not browned, while the latter is mostly blocked by rhizome-transmitting tissue. When sun exposure and evaporation of plant water are large, wilting and dead seedlings appear after wilting, and browning occurs in root and stem tubes. 5. Growth stagnation: The symptoms of slow growth caused by phytotoxicity are often associated with spots or other phytotoxicity symptoms compared with the symptoms of stiffness or lack of physiology caused by physical diseases. Poisoning is often characterized by poor root growth. The deficiency of the disease is manifested as yellow or dark green leaves. Third, remedial measures Spraying with water: If the leaves and plants cause phytotoxicity due to spraying liquid, they can quickly spray the leaves with plenty of clean water when the early liquid has not been fully penetrated or absorbed. Rinse 3 to 4 times repeatedly to try to get the medicine on the surface of the plant. The liquid is flushed out and cooperated with the cultivator loose soil to promote the development of the roots, so that the plants quickly return to normal growth. 2. Topdressing available fertilizer: After the occurrence of phytotoxicity, timely watering and topdressing urea and other available fertilizers. In addition, foliar spray of 1% to 2% urea or 0.3% potassium dihydrogen phosphate solution is also required to promote plant growth and increase their ability to resist phytotoxicity. 3. Use of antidote or plant growth regulator: According to the nature of pesticides causing phytotoxicity, neutralize the drug with its opposite nature. For example, after applying excessive amount of copper sulfate, 0.5% of quicklime water can be sprayed. After spraying paclobutrazol, the amount of gibberellin can be relieved after being sprayed, and foliar spraying can also be used. 4. Irrigation and washing of fields: For fields with excessive soil application, irrigation should be carried out as soon as possible so that a large amount of drugs can be expelled out of the field with water, so as to reduce phytotoxicity. 5. Remove the victim: timely remove the victim's fruit, branches and leaves, and prevent the agent in the body from continuing to conduct and infiltrate.
Better Medical Technology Co., Ltd. , http://www.fshospitalbed.com