Identification of pesticide phytotoxicity symptoms
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(2) Yellowing Yellowing can occur in the stems and leaves of plants, and more yellowing occurs in the leaves. The main cause of yellowing is that pesticides hinder the normal photosynthesis of chlorophyll. The mild appearance is yellowing of the leaves, and the severe occurrence is yellowing of the whole plant. Leaf yellowing has the yellowing of the heart leaf and the yellowing of the base leaf. The yellowing caused by phytotoxicity is different from the yellowing caused by lack of nutrients. The former often turns from yellow leaves to dead leaves, and there are many sunny days. The yellowing is rapid, the rainy days are more, and the yellowing is slower. The latter is often associated with soil fertility, and the whole plot of yellow seedlings is consistent. 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 healthy plants in the field.
(3) Malformations Malformations caused by phytotoxicity can occur in the stems and roots of crops, and common are rolled leaves, clumps, swollen roots, deformed ears, and deformed fruits. The malnutrition of the drug is different from the malformation of the virus. The former is common and the local symptoms are manifested on the plant. The latter often occurs sporadically, showing systemic symptoms, often mixed with broken green veins and wrinkles.
(4) Withering The phytotoxicity of the wilting often causes symptoms of the whole plant, mostly caused by herbicides. The wilting caused by phytotoxicity is different from the wilting symptoms caused by the disease in the plant. The former has no morbidity center, and most of the process is slow, first yellowing, post-mortem, and no browning of the rhizome. The latter is mostly rhizome conduction. The tissue is blocked. When the sunlight is irradiated and the amount of evaporation is large, the first wilting occurs, and then the green dead seedlings are lost. The root catheter often has browning.
(5) Growth stagnation This kind of phytotoxicity inhibits the normal growth of crops and slows the growth of plants. This phenomenon is generally caused by herbicide phytotoxicity, but it is only different. The stagnation caused by phytotoxicity is more complicated with the stiffness and deficiency of physiological diseases. The former is often accompanied by symptoms of drug touch or other phytotoxicity, while the latter is characterized by poor root growth and dysfunction. The color is yellow or dark green.
(6) Infertility Infertility is a kind of phytotoxicity caused by improper use of crops during reproductive growth. Infertility caused by phytotoxicity and infertility caused by climatic factors are different. The former is a whole plant infertility, sometimes it is partially strong, but mixed with other phytotoxicity symptoms; and the climate-induced infertility has no other symptoms, and rarely occurs all. Infertility phenomenon.
(7) Shedding Most of them are expressed in fruit trees and some dicotyledons, with symptoms such as falling leaves, falling flowers, and falling fruits. Pay attention to the defoliation, falling flowers, fruit drop caused by phytotoxicity and the defoliation, falling flowers and fruit falling caused by the atmosphere or cultivation factors. The former is often accompanied by other phytotoxicity symptoms, such as yellowing, dry coke, and then falling leaves. The latter is often associated with severe weather and often occurs during high winds, heavy rains, and high temperatures.
Hua County Wu Limin