How to improve the effect of preventing diseases and insects with fertilizer?

One of the biggest problems to be dealt with in the planting process is disease and insect control, and we can solve this problem through reasonable fertilization. So, how to improve the effect of preventing diseases and insects with fertilizer?

First, how to improve the effect of preventing diseases with fertilizer?

Rational fertilization can not only promote crop growth, but also reduce the occurrence of diseases. For example, spraying 1% and 3% superphosphate solution on wheat at jointing and heading stage can improve the resistance to stripe rust and reduce the disease; the application of potassium fertilizer can improve the resistance of rice to rice blast, rice sheath blight, cotton wilt, potato late blight, tomato spot blight, etc. Copper fertilizer can improve the resistance of tomato to leaf mildew and sugar beet to brown spot.

There are five reasons why fertilizer can prevent diseases and enhance the disease resistance of crops.

① directly killed the pathogen. For example, lime nitrogen and its transformed intermediates have special toxicity to pathogens; zinc has the ability to directly poison pathogens, has a fixed effect on viruses, and hinders the upward movement of pathogens; copper and manganese are also toxic to pathogens

② enhances the resistance of host crops to bacterial infection, such as silicification of epidermal cells after the application of silicon fertilizer, potassium fertilizer can promote the formation of cellulose and lignin, making it difficult for bacteria to invade the body, and appropriate amounts of calcium, boron and zinc can improve the stability of epidermal cell membrane and reduce the outflow of nutrients, thus reducing bacterial infection.

③ promotes the formation of phenolic compounds in plants. It is generally believed that crops or varieties with high phenol content in the body have strong disease resistance because phenol has bactericidal effect. Proper application of potash fertilizer could increase the phenol content in millet leaves and reduce the harm of vermicularia, but partial application of nitrogen fertilizer could reduce the phenol content and be susceptible to disease.

④ promotes protein formation. It is generally believed that glutamic acid, aspartic acid and their amides are good nitrogen sources for pathogens and are conducive to their reproduction. The application of potassium fertilizer can promote the formation of soluble nitrogen into protein, so the disease resistance of crops is improved. Many trace elements such as boron, zinc, molybdenum and manganese can promote protein synthesis and reduce the content of amino acids in the body, which is an important reason for the improvement of crop disease resistance by proper application of trace elements.

⑤ promotes starch formation. The disease resistance of crops is closely related to the starch content in the body, because the starch content is high, the soluble nitrogen content is low, and the ratio of carbon to nitrogen is high, which is not conducive to the reproduction of bacteria, so it is not easy to get sick. According to the study, the starch content in rice is the lowest at tillering stage and heading stage, which is the period when rice blast is easy to occur. Phosphorus and potassium fertilizer can promote photosynthesis and starch formation, so it can enhance disease resistance. Trace elements such as iron, manganese, zinc and copper are essential for normal photosynthesis. The formation of high molecular carbohydrates is also inseparable from trace elements, and when trace elements are deficient, crop disease resistance is weakened.

In order to improve the effect of preventing diseases with fertilizer, we can start from the following three aspects:

① attaches importance to the balance of nutrient elements. The combination of nitrogen, phosphorus and potassium fertilizer, and the combination of large and medium elements with trace elements to enhance the disease resistance of the plant.

Organic fertilizer was applied to ②. Organic fertilizer contains a large number of microorganisms, which can antagonize diseases, especially soil-borne diseases.

③ changes the pH of soil. Many soil-borne pathogens are fungi and are sensitive to ammonia. Therefore, the application of ammonia has a strong germicidal and disease control effect on wheat total erosion pathogen, cotton Verticillium wilt and cotton Fusarium wilt.

Second, how to improve the effect of pest control with fertilizer?

In production practice, it is found that some fertilizers can not only promote crop growth, but also play a role in pest control, such as silicon fertilizer has a better control effect on rice borer, rice planthopper and bean borer, cotton can control cotton bollworm after spraying calcium superphosphate; manganese application can reduce the harm of barley aphids, grape aphids and sugarcane root drills; boron application can reduce the harm of mites; ammonium bicarbonate also has pest control effect.

There are three main reasons why fertilizer can control insect pests:

Some pests in ① are repellent to the chemical composition of some fertilizers, such as cotton bollworm to the phosphorus element in calcium superphosphate.

② fertilizer can enhance the insect resistance of crops, for example, silicon fertilizer can make the epidermis cells silicified and insects more difficult to invade, and copper and boron can enhance the insect resistance of crops by participating in the formation of lignin.

Some fertilizers of ③ have strong stimulation, corrosion, fumigation and insecticidal ability. Such as ammonium bicarbonate, it is very easy to kill some small, weak tolerance pests.

We should also pay attention to the methods of preventing insect pests with fertilizer. If superphosphate is used to control Helicoverpa armigera, according to the growth and occurrence characteristics of Helicoverpa armigera, it is necessary to grasp the avoidance of phosphorus in Helicoverpa armigera during oviposition, so fertilizer should be applied in the second, third and fourth generation of Helicoverpa armigera. Generally, 1% superphosphate extract is used for extra-root topdressing to drive the cotton bollworm to a place to lay eggs, and then gather and annihilate, which can not only control cotton bollworm, but also promote cotton early maturity and high yield.