The bispyribyl ether effectively prevents weeds and other grass weeds in rice fields, and treats most broad-leaved weeds, some sedge weeds, and valerian which are resistant to other herbicides . Pay attention to the following seven major issues when using bispyrrole

one, Strictly control the application period and strictly control the application rate

Due to the extremely high activity of bispyribyl ether, the application period must be strictly controlled. Both indica and japonica varieties should be controlled after the 5-leaf stage. Although some manufacturers claim to add succinic ether in the 3-leaf stage (seed period) after adding special additives, this promotion method lacks sufficient verification. After the 5-leaf stage, the degradation ability of rice to bis-oxalyl was significantly enhanced, and the safety was greatly improved. The recommended dosage of 100g/L bis-cephate is 20mL-30mL. Due to the compound resistance of bispyribac and quinclorac, the actual application amount in some areas is 30mL-40mL. However, for areas that have not been used, the principle of pre-testing and promotion should be followed, and the amount of application should not be too large.

two, Bispyribac the difference in selectivity for different varieties of rice

There is a difference in the choice of bispyribyl ether for different rice varieties. The safety difference of bispyribyl ether to different rice varieties and different leaf stages is mainly caused by the difference in the metabolic capacity of the important metabolic enzyme GST in plants. This difference is manifested by the increasing sensitivity of indica, hybrid rice and japonica rice (indica) to bispyribac. In the application, no matter whether it is used in the three-leaf stage of japonica rice or japonica rice, there will be chlorosis. After the three leaves are used, the japonica rice is safe, and the japonica rice must be used after the five-leaf period. In the case of weak seedlings, sudden changes in temperature difference, and high application rate, chlorosis will occur after 3 days of application, and it will generally return to green at 10d-15d. In the promotion guidance, it is necessary to adjust the appropriate dosage and application period in combination with the planting varieties in the area.

three, Pay attention to temperature changes

Suitable temperatures for the application of bis-oxalate range from 15 degrees to 35 degrees. In the appropriate temperature range, the control effect of bispyribac on weeds increased linearly with increasing temperature, and the safety was better. When the temperature is lower than 15 degrees, the control effect of bispyribac is unstable. At the same time, the decrease of physiological metabolism level of rice increases the probability of occurrence of phytotoxicity. When the application of high temperature above 35 degrees continuously occurs, it is also easy to cause phytotoxicity. In the southern region, especially in the middle and lower reaches of the Yangtze River, the temperature changes during the early rice application period, and attention should be paid to temperature changes during use.

The natural degradation of bispyribac is also related to temperature. As the temperature increases, the degradation rate of bis-oxalate increases and the half-life is shortened. For every 10 degrees increase in temperature, the hydrolysis rate of bispyribyl ether increased by a factor of 1.6. Therefore, the storage of bispyribyl ether should avoid high temperatures. The application of bispyribac at high temperature is beneficial to the efficacy of the drug, and may also shorten its efficacy period and reduce the control effect.

four, Note the complex resistance to quinclorac

It has been reported in the literature that after the application of cyhalofoprin and bis-oxalate for two consecutive years, the valeric acid-resistant valerian has resistance to cyhalofop-butyl ester and bispyribofin. Drug resistance. In some areas where bis-oxalate has been used, it is necessary to pay attention to this and be cautiously optimistic about field control to avoid high inventory due to poor control.

Fives, Drain first, then take medicine, then rehydrate

Before the application, it is necessary to drain the water in the field to expose the weeds and keep the fields moist. After 1 d of treatment, rehydrated and kept the shallow water layer for 7 days, followed by normal field water management. Tests have shown that re-watering after drainage first has a great impact on the efficacy of bis-oxalate. In addition, the safety performance of bispyribyl ether in dry field is better than that of direct seeding and transplanting (machine transplanting), so pay attention to the depth of the water layer in the field.

six, Pay attention to the environmental pH and affect the control effect of bispyribac

As the pH continues to decrease, the degradation rate of bis-oxalate continues to increase. In practical applications, the three commonly used fertilizers of potassium dihydrogen phosphate, ammonium hydrogencarbonate and urea, because the potassium dihydrogen phosphate ionizes H+, the degradation rate of bispyribyl ether becomes larger, while the ammonium hydrogencarbonate and urea are alkaline and water-soluble. The effect period of the drug effect becomes longer. At the same time, the difference in the pH of the organic matter content of different soils also affects the degradation rate of bispyribac ether, which affects the control effect to some extent.

Seven, Inhibition of ALS on rice ALS

Under reasonable dosage, bis-oxalate had no inhibition on indica ALS after 5 leaf stage. The inhibition of ALS on indica rice peaked at 5d, then gradually decreased, and there was no inhibition at 9d. In the field, the indica rice began to have yellowing and chlorosis in 3 days, and began to recover after 10 days, and returned to green. This short-term inhibition on indica has no effect on the final yield formation. Interpretation should be done for the first time using bispyridyl ether.