(1) Spot: It mainly occurs on the leaves of crops. There are several kinds of spots, such as brown spots, yellow spots, dead spots and net spots. The main difference between the drug spot and the physiological disease spot is that the former is often irregular in the distribution of the plant, while the latter is generally common, and the symptoms of the plant are more consistent; the difference between the drug spot and the fungal disease is the size of the former spot, and the shape changes greatly. The latter has a disease center and the spot shape is more consistent. (2) Yellowing: It is expressed in the stems and leaves of plants, and more leaves occur. The yellowing caused by phytotoxicity is compared with the yellowing of nutrient deficiency. The former tends to develop from dead leaves to yellow leaves, and the whole field is light and heavy. The latter tends to show consistency in whole field yellow seedlings. Compared with the yellowing caused by the virus, the yellow leaves of the latter often have a greenish appearance, and the diseased plants exhibit systemic symptoms, which are mixed with the healthy plants in the field. (3) Malformation: manifested in the stems and roots of crops. Common malformations include leaf rolling, clumping, swollen roots, deformed ears, and deformed fruit. (4) Withering: Most of these diseases are caused by improper use of herbicides. There is no disease center in the wilting of the phytotoxicity, and the process is slower, first yellowing, and the dead plant has no browning at the base of the rhizome. (5) Stop growing: the growth of plants is slow, and the herbicides of common herbicides inhibit growth. (6) Infertility: Inappropriate use of the crop during the growing season of the crop can cause infertility. (7) shedding: manifested in fruit trees and some dicots, with symptoms of falling leaves, falling flowers and falling fruits. (8) Inferior fruit: The main manifestation is that the fruit volume of the plant becomes smaller, the fruit performance is abnormal, the quality is deteriorated, and the food and economic value are affected.
Second, the distinction between acute phytotoxicity and chronic phytotoxicity
(1) Acute phytotoxicity: Acute phytotoxicity refers to the symptoms manifested within 10 days after application. Generally occur faster, the symptoms are obvious, mostly manifested as spots, chlorosis, burns, wilting, falling flowers, fruit drop, leaf curl, deformity, tender tissue of young tissue. ⑵ chronic injury: after application there will be dozens of genius injury symptoms, and the symptoms was not obvious, physical activity primarily affects crops, where there is yellow, slow growth, deformity, small fruit, bad fruit and so on.
Third, remedies
⑴ large or slightly alkaline water, rinsing water rinse: the discovery of an earlier injury, with plenty of water can be quickly sprayed foliar phytotoxicity of crops, plants try to wash off the surface of the medicament, in addition, since a large current most pesticides are relatively easy to meet the basic substance reducing effect can be added in an appropriate amount of water sprayed 0.2% or 0.5-1% solution of baking soda lime, rinsed or washed, to accelerate decomposition of the agent. At the same time, because a large amount of water is used for leaching, the crop absorbs more water, increases the water in the crop cells, and can play a certain dilution effect on the concentration of the medicament in the crop, and can also reduce the phytotoxicity to a certain extent. . (2) Rapidly apply quick-acting fertilizer: quickly apply urea and other quick-acting fertilizers on crops where phytotoxicity occurs, increase nutrients, increase the vigor of crops, promote early growth, and accelerate crop recovery. This is a less sensitive seed bud and seedling. The effect is obvious. ⑶ spraying ease the injury of drugs: drug leads for the injury occurred, spraying of pesticides can alleviate the injury. If the crop is poisoned by omethoate, 0.2% borax solution can be sprayed on the crop; the phytotoxicity caused by copper sulfate or Bordeaux mixture can be sprayed with 0.5% lime water. (4) Removal of sites with serious phytotoxicity: This measure is often used on fruit trees. For example, in fruit trees, methods such as perfusion, injection, and dressing are used, and insecticides with strong systemic absorption are used. If the concentration of the pesticide is too high, the damaged branches should be quickly removed to prevent the medicament from continuing. Conduction and penetration. At the same time, water is quickly poured to prevent the phytotoxicity from continuing to expand.
Identify pesticide remedies and remedies
First, the characteristics of phytotoxic lesions and physiological lesions
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