What are the specific drugs for Plutella xylostella?

What are the hazards of Plutella xylostella? What are the specific drugs for Plutella xylostella? Plutella xylostella is a worldwide migratory pest. Plutella xylostella mainly harms cabbage, purple cabbage, cauliflower, cabbage, mustard, cauliflower, cabbage, rape, radish and other vegetable plants. Therefore, the farming network has sorted out the harm and control methods of Plutella xylostella. The following details are listed for netizens' reference. The harm of Plutella xylostella: the first instar larvae of Plutella xylostella feed on plant mesophyll, leaving epidermis, forming transparent spots on leaves and forming leaf voids; the 3rd and 4th instar larvae of Plutella xylostella can eat vegetable leaves into holes and lacerations. in severe cases, the whole leaf is eaten into a net. In the crop seedling stage, the central leaves are often harmful, affecting the heart. Plutella xylostella also harms young stems, young pods and seeds. The occurrence of Plutella xylostella showed two peaks in the whole year, the first from mid-May to late June and the second from late August to late October. Reasons why it is difficult to control Plutella xylostella: first, Plutella xylostella is small, as long as a small amount of food can survive, easy to avoid the enemy. Second, Plutella xylostella has strong ecological adaptability, can survive the short-term cold of minus 15 degrees in winter, and can also feed in the environment of-1.4 degrees. Summer can survive the heat above 35 degrees, and only the torrential rain in summer can kill them in large numbers. Third, Plutella xylostella has strong drug resistance. Due to the long-term use of chemical pesticides to control and kill a large number of natural enemies, the damage of Plutella xylostella is increasing day by day, and soon produced a very high level of resistance to all kinds of chemical pesticides. In the 1990s, there was no cure for the rampant Plutella xylostella in many places. Due to the large occurrence area, long damage time and difficult control, Plutella xylostella gradually replaced Pieris rapae and became the No. 1 pest of vegetables. Fourth, the life cycle of Plutella xylostella is short, feeding on cabbage, when the temperature is 28-30 degrees, it takes as long as 10 days to complete a generation. The control methods of Plutella xylostella: method 1. Trapping the diamondback moth using the phototactic habit of diamondback moth, trapping adults with black light or other light sources at 7: 11 at night. Trapping is mainly carried out from April to May, or other light sources to trap adults. Method 2. Release the natural enemies of Plutella xylostella to control the harm. Among them, Plutella xylostella, Plutella xylostella and Plutella xylostella controlled the number of Plutella xylostella most obviously. Method 3. Bacillus thuringiensis was sprayed with 8000 international units / ml per mu and diluted 500 to 1000 times; the dosage should not be too high or too low, focusing on the control of low instar larvae, especially the 1st and 2nd instar larvae; to avoid high temperature, preferably in sunny afternoon or cloudy days, but not when the temperature was lower than 15 ℃; spray the back of vegetable leaves. Method 4. The dosage of 1% methylaminoavermectin EC is 15-25 ml / mu and sprayed with 50 kg water. The diamondback moth (Plutella xylostella) was sprayed from the peak hatching period of the eggs to the second instar of the larvae. Or use a dose of 5% fipronil suspension 20-40 ml / mu with 50 kg of water spray. The diamondback moth (Plutella xylostella) was sprayed from the peak hatching period of the eggs to the second instar of the larvae. You can also use a dose of 10% fipronil suspension 35-50 ml / mu, 50 kg spray with water. The diamondback moth (Plutella xylostella) was sprayed before the peak hatching period of eggs or the 2nd instar larvae. What is Bacillus thuringiensis? Control methods of whitefly