aphid
1, Harm: There are two kinds of aphids that harm vegetables: vegetable aphid (radish aphid) and peach aphid, which are the main pests of vegetables. Both adults and nymphs of these two kinds of vegetable aphids suck vegetable juice, which makes their leaves curl and turn yellow, makes plants short and can spread viral diseases. The cabbage aphid occurs once a year 10-20 generations, and overwinters on the heart leaves or back of the host with wingless aphids. Winged aphids and wingless aphids are produced in March and April of the following year, and they change their owners in cruciferous vegetables all the year round. But autumn is the most harmful. Myzus persicae has 20-30 generations a year, wingless aphids overwinter on the back of the heart leaves or leaves of the host or overwinter as eggs, hatch in March-April of the following year, and a large number of winged aphids migrate in May. Until winter. Male aphids can produce more than 10- 100. When the climate is suitable, they can lay eggs every 4-5 days, which is more harmful in dry years.
2. Control method: Shenzhen Ruide Gaochan 1500 times 40% dimethoate emulsion, 3,000 times 4.5% beta-cypermethrin or 1500 times Keyibao can be sprayed.
diamond back moth
1, Hazard: Plutella xylostella larvae, commonly known as "double-headed sharp", are another major pest that harms vegetables. The first instar larvae burrow into tissues to eat mesophyll, the second instar larvae begin to eat mesophyll, and the third instar larvae burrow into holes or meshes after eating leaves. Plutella xylostella has 9- 10 generations a year, and adults, pupae and larvae can overwinter. When the weather gets warmer, adults begin to move, and most eggs are laid on the back of leaves near veins. The average number of eggs laid by a female moth can reach 300. Plutella xylostella generally occurs in April-65438+1October, especially in April-May and August-September, which is very harmful.
2. Control method: 800-fold solution of 90% crystal trichlorfon or 25% zhongkemeiling 1500-2000-fold solution can be sprayed.
cabbage caterpillar
1, Hazard: Pieris rapae is also called caterpillar, and the adult is Pieris rapae, also called Pieris rapae. Larvae damage leaves and eat them into holes or gaps. In severe cases, the whole leaf is eaten up, leaving only petioles and veins. Pieris rapae has 8-9 generations a year, and overwinters as pupae in June 5438+065438+1October. The first generation of adults began to occur in mid-March. Adults suck nectar during the day and like to lay eggs on cabbage and cauliflower. Each female moth can lay eggs 100-200 for 3-8 days. Larvae * * * is the fifth instar. Before the third instar, its food intake is small and its drug resistance is poor.
2. Control method: Chemical control is the same as Plutella xylostella.
Vegetable borer
1, Hazard: The larvae of Plutella xylostella are commonly known as borers. The newly hatched larvae spin a web in the heart of the seedling and feed on the leaves of the heart. After the third instar, they can drill from the heart leaves to the roots, causing the roots to rot. Vegetable seedlings suffer the most when they grow 3-4 leaves. Pieris rapae has 6-7 generations a year, and the larvae spin silk in the soil, stick to the dead leaves of the soil to build nests and overwinter in bags. The next spring, cocoons formed on the fallen leaves in the soil or on the ground. After eclosion, adults move at night, and their eggs are scattered on the leaves, mostly in the heart leaves. Larvae has the characteristic of turning to the main body to harm, and mature larvae cocoon and pupate in the soil near the roots of plants.
2. Prevention and control methods: remove weeds, dead plants and leaves in the field, and eliminate pupa cocoons. Spraying 800-fold solution of 90% crystal trichlorfon or 25% zhongkemeiling 1500-2000-fold solution at the vegetable seedling stage, that is, before the larvae spin silk.
Yellow-curved flea beetle
1, Harm: The yellow striped flea is commonly known as flea, and the larva is commonly known as white maggot, which is also one of the main pests that harm vegetables. Both adults and larvae of striped flea beetle can cause damage. Adults mainly feed on leaves and can also harm tender stems, buds and pods. Larvae peel or eat the root bark or eat the root to form a tunnel, which makes the plant wither. The striped flea beetle occurs 5-6 generations a year, overwinters as adults in soil gaps, the reverse side of vegetable leaves on the ground, residual plants and weeds, and continues to move and feed when the temperature is warm. Overwintering female adults can lay about 600 eggs per head. After hatching, the larvae eat vegetable roots, and the mature larvae pupate at a depth of 3-7 cm below the soil surface.
2. Prevention and control methods: After autumn, weeds and dead leaves in the field will be cleared, and overwintering adults will be eliminated. When weeds grow in early spring, they should be pulled out in time so that overwintering adults have no proper food. When adults are found, they should be sprayed with 800 times of 90% crystal trichlorfon or 25% zhongkemeiling 1500-2000 times. Larvae can be eliminated by spraying the above chemicals on the soil surface.