Recently, some farmers consulted on the prevention and control methods of weeds in wheat fields after jointing. There are two main situations, one is the wheat field with poor chemical removal effect; and the other is the wheat field without chemical removal.

At present, there are many kinds of herbicides for wheat, and most varieties are required to be used before wheat jointing, and it is not suitable to use medicine after wheat jointing. The main reasons: 1. Wheat and weeds have different sensitivity to herbicides in different periods, and their safety performance to wheat is also different. After the jointing of wheat, it is the period of simultaneous vegetative growth and reproductive growth of wheat. It is poorly resistant and sensitive. It is easy to cause curling of wheat leaves, yellowing of wheat seedlings, growth inhibition, destruction of ear differentiation, failure of normal earing or wheat ear deformities. 2. Spraying herbicides containing tribenuron-methyl can easily cause damage to subsequent crops such as cotton and soybeans. The interval between the application period and the sowing period of the next crop should not be less than 60 days to ensure the safety of subsequent crops.

For the above reasons, the wheat fields that have been sprayed with herbicides can no longer be removed after jointing, and manual removal can be adopted. For wheat fields that have not been sprayed with herbicides, you can choose carfentrazone contact selective herbicides, or you can choose diflufenazone systemic conductive postemergence herbicides. These two herbicides are easily degraded in the soil and have a longer half-life. It is short and will not cause phytotoxicity to the following crops. It can be used to control broad-leaved weeds such as Artemisia sowing, shepherd's purse, quinoa, Phenix sylvestris, Kochia scoparia, Sodium spp. In order to ensure safety, pick-and-curve methods can be used when applying pesticides in the field, mainly spraying the pesticides on areas with a lot of weeds, but be sure not to repeat spraying to prevent excessive local application of pesticides from adversely affecting wheat.

We all know that wheat and weeds have different sensitivity to herbicides at different periods, and their safety performance to wheat is also different. Various herbicides have different performances. Therefore, it is important to correctly grasp the application period, especially after the jointing of wheat. When applying pesticides to the differentiation stage of young ears, more attention should be paid to the safety of herbicides to wheat. At present, there are many types of herbicides for wheat, and most varieties are required to be used before the jointing of wheat, and it is not suitable to use the medicine after the jointing of wheat, otherwise it is easy to cause different degrees of phytotoxicity.

For example, toluene mixture can prevent a variety of broad-leaved weeds. Use 125 ml of 20% dimethyltetrachloride water and 100 ml of 40% Bentazone water per acre, spray 30 kg of water, and spray the time with wheat tillers. It is suitable before the later jointing, and the mixture is only suitable to be applied to the crops that are rice after the stubble. Wheat, rice and other gramineous crops are very sensitive to dimethyltetrachloride at the seedling stage. After the 3-4 leaf stage, the resistance gradually increases, the strongest at the end of tillering stage, and the sensitivity increases again at the young ear differentiation stage. Therefore, it is generally required to be in the crop 4 Apply medicine from leaf stage to before jointing. 40% Baicaodi and 2,4-D butyl ester cannot be used after wheat jointing, otherwise it will easily cause phytotoxicity to wheat. If used too late, the wheat will not set grains. Wheat is applied at the jointing to booting stage, which is the period of simultaneous vegetative growth and reproductive growth of wheat. The resistance to pesticides is poor and sensitive, and it is easy to produce phytotoxicity, inhibit wheat growth, cause tiller death, malformed wheat ears, and slow growth. Therefore, it should be applied before jointing. For example, at the jointing and booting stage of wheat, it is more sensitive to a variety of herbicides such as puma, dimethyltetrachlor, dicamba, etc. After application, it is easy to cause wheat leaf curling, yellowing of wheat seedlings, growth inhibition, Destroy ear differentiation, failure of normal earing or malformation of wheat ears. The application of herbicides containing tribenuron-methyl in wheat fields in spring is likely to cause damage to subsequent crops such as cotton seedlings and soybeans. It should be applied before winter and the interval between the sowing period and the next crop should not be less than 60 days to ensure the success of subsequent crops. Safety.

In the spring wheat field, weeds of Heping family, such as Mai Niang, should be controlled, and herbicides such as Puma should be used. Isoproturon has a good control effect on weeds with small leaf age, while the weeds at the jointing stage of wheat are older, and the application of isoproturon has a poor weed control effect.

Relatively speaking, the herbicides suitable for controlling broad-leaved weeds in wheat fields, such as Kuimilan and Ditaron, are safer for wheat seedlings. Application after jointing of wheat generally does not have much impact on the growth and development of wheat. The residual period of these herbicides in the field is short, and the application of the herbicide in the wheat field in spring will not have an adverse effect on the following crop. Tribenuron-methyl and other herbicides have a long residual effect, and generally should not be applied after jointing of spring wheat to avoid phytotoxicity to subsequent crops.

Taking into account that the application of herbicides may have adverse effects on the jointed wheat, the method of picking and curing can be used when applying the herbicide in the field. It is mainly to spray the weeds in areas where there are a lot of weeds. At the same time, it should be noted that even in areas with a lot of weeds, Do not blindly repeat the spray to prevent the excessive local dosage from causing adverse effects on the wheat.