Glyphosate is a highly effective herbicide that cannot be used in paddy fields. There are various content and dosage forms of glyphosate, such as 10% water, 41% glyphosate isopropylamine saline, 30%, 60% wettable powder, 90%, 95% glyphosate original powder, etc. 10% glyphosate aqueous solution is the most widely used.
In terms of production, every year a small number of farmers use large doses of glyphosate to kill weeds when paddy fields, especially seedling fields, are plagued by weeds. Due to the harm of residual glyphosate pesticides in the soil, the seed setting rate is significantly reduced. Attention is needed.
Do not use glyphosate to kill weeds in paddy fields, including ridges. Glyphosate is sprayed on the ridge, and the mist drifts to the seedlings or seedlings, which will cause obvious phytotoxicity. In the booting and heading stages of rice, the use of glyphosate sprayed and uncleaned medical equipment can easily lead to phytotoxicity.
The ears of rice that failed to harvest have been investigated, and the ears are shortened to only about normal, and the spikelets are deformed, only about 1/3 of the normal size, and the normal flowering and seed-setting rate cannot be achieved.
According to the production survey: when the weeding concentration of glyphosate reaches 1 000 ppm, the rice plants will turn chlorotic and die prematurely; while at the lower concentration of 300 ppm, the rice will not show the phenomenon of fading and dead stalks, but will cause the rice plants to die. A series of allergic reactions, mainly manifested in the following points:
①The heading of rice is seriously hindered, and there are no heading, deformed ears, etc. Although some can be heading normally, the resulting paddy is not strong and mostly empty grains. In some cases, the phenomenon of the same position and low position multi-spike occurs;
②The tillering of plants increased, and the phenomenon of high-node tillering and high-node root system appeared;
③ The flag leaves are shortened and shrunk, often 1/3 to 2/3 shorter than normal plants, and some flag leaves are less than 5 cm in length. The leaves of the affected plants are dark green at the later stage of growth, and there is little yellowing phenomenon;
④The damage of rice in different growth stages. The agricultural technology department has observed the symptoms of low-concentration glyphosate injury in hybrid rice, and found that when the rice is damaged during the tillering stage, the plants appear dwarfed 4 to 5 days after the treatment, the leaves of the rice turn yellow, and the stem nodes at the base of the rice begin to rot. The leaves of the heart withered and rolled longitudinally into a whip shape, forming a false dead heart (which most rice farmers mistaken for the dead heart caused by borers or mole crickets). About 7 days later, tillering began. There were many tillers. The plants were dark green and clustered. Aerial roots appeared on the basal nodes of the affected rice.
The young panicle is damaged at the differentiation stage, the growth of the main stem is inhibited, the plants become shorter, the internodes become shorter, aerial roots also appear on the nodes, and the tillers increase, forming a multi-headed disease. Injured at the booting stage, the rice plants often fail to head, the cob stems are light brown to brown, and the tissue is necrotic, but the rice leaves are normal and do not die.
Observation of phytotoxicity caused by misuse of low-concentration glyphosate in single-season late rice. It is found that the leaves turn green in the afternoon after spraying on a sunny day in the tillering stage, and the leaves of the heart become wilted on the second day, and the heart leaves recover at night. Unrolled, the heart leaves were re-rolled into false withered hearts on the third day, and the heart leaves turned yellow and died on the fourth day, and the plants dwarfed. After a week, the plants had more tillers, dense green clusters, and good root growth. After another 10 days, aerial roots appeared in the internodes of rice stems, and young panicle differentiation appeared at the top of the stems.
