Pay attention to the use of post-emergence herbicides in corn fields

According to the situation of drug damage and weed control effect caused by herbicide after seedling application in corn field for many years, this paper puts forward the requirement of weeding after spraying seedling, in order to achieve good weed control effect in the field and protect corn from drug damage. First, when applying pesticides in corn fields, do: "make a clear distinction between varieties and do not use drugs blindly." As the current corn post-seedling herbicides are mostly nicosulfuron, some corn varieties are sensitive to this ingredient and are prone to drug damage. Some products are forbidden to be used in corn inbred lines, sweet corn, sticky corn, Denghai series and other varieties, so it is said that post-seedling herbicides can not be used in all kinds of varieties, and the instructions of the products should be read in detail. If you can use it, you will not use it improperly, so as to prevent and control drug damage caused by corn seedlings. Second, the dispensing should be done: "second dilution, no direct mixing of water and medicine", especially powder medicine. Secondary dilution is like a cook making noodle porridge, under the premise of selecting a certain amount of water, first mix a small amount of water evenly with the medicine, and then add the remaining water, stir evenly and then spray. Avoid due to uneven mixing of water and medicine, the weeds die in this area where the medicine is sprayed, and the weeds continue to grow in the place where the water is sprayed. Third, do "low spray, not high spray" when spraying. The term "low and high" here refers to the low and high temperature. In other words, spray before 9 a. M. and after 4 p. M. on the cooler days of the day. Do not spray in the morning, noon or afternoon when the temperature is high and the weather is dry, so that the amount of herbicides entering the weeds is limited and the absorption is insufficient, which affects the herbicidal effect. At the same time, high-temperature spraying corn seedlings are also prone to drug damage. Fourth, do: "spray small, not old" when weeding. Catch weeds from two leaves to four leaves. Weeds are sprayed in a favorable period with a certain drug area and low resistance. Don't wait until the weeds grow to more than 10 centimeters tall and spray them when your eyes are clear green. In years of high temperature and drought, although weeds are short, they form "small old grasses" with gray leaves because of their long growth time and well-developed roots. Should increase the amount of liquid sprayed, not less than 40 kg per mu, spray the whole plant of weeds evenly, do not hesitate to save water, otherwise you can not achieve the effect of eliminating weeds. Fifth, when weeding and pest control, do: "mixed with pyrethroid pesticides, never mixed with organophosphorus pesticides." In order to save labor and time, when spraying post-seedling herbicides, weeding and pest control can be carried out at the same time when insect pests occur in the seedling stage of corn field. But mixed pesticides should choose pyrethroids and carbamate insecticides, spray to avoid heart leaves as far as possible, anti-drug liquid perfusion. In the years when the occurrence of flies or thrips in Sweden is serious, although herbicides can be mixed with imidacloprid or acetamiprid, it is necessary to spray heart leaves to control these two kinds of insects. if they are mixed with herbicides to control insects, corn seedlings are prone to drug damage, so herbicides should be sprayed in front and imidacloprid or acetamiprid should be sprayed behind to avoid drug damage to corn seedlings. One week before and after spraying herbicides, it is strictly forbidden to spray organophosphorus insecticides, otherwise corn seedlings will cause drug damage. Sixth, corn seedlings after the five leaves to achieve: "set a spray, not spray all over the field." The best spraying time for weeding after seedling is the 2th and 5th leaf stage of corn. If the best period is missed and weeding is necessary, it should be sprayed along the ridge and should not be sprayed all over the field, so as to avoid drug damage. Otherwise, the light ones will cause the corn heart leaves to turn yellow, the heavy ones will turn white, and the whole plant will stop growing.