Cabbage is the most common pest on cruciferous vegetables. Its adult is called cabbage butterfly. There are five species in China, namely, cabbage butterfly, spotted butterfly, large cabbage butterfly, oriental butterfly, and brown butterfly. All belong to the order Lepidoptera, Pieridae. All countries in the world are distributed. Among them, the cabbage butterfly is the most common in China, and it is the most serious. The larvae of the cabbage butterfly are called cabbage caterpillars. There are 35 species of host plants known to belong to 9 families. Such as cruciferae, Compositae, Broccoli, Ordothaceae, Oleaceae, Comfrey, Liliaceae and so on. But mainly for cruciferous vegetables. Such as: Ganlan, broccoli, cabbage, indigo, radish, mustard, rape and so on.
At the early age of the cabbage larvae, the mesophyll is eaten in the leaf back, and the epidermis remains, which is a small concave plaque. After 3 years of age, the leafy meat is eaten into a hole or a block. In severe cases, only the veins and petioles remain. At the same time, a large amount of feces is discharged, polluting the leaves and the heart of the vegetables, which deteriorates the quality of the vegetables, and provides an invasive route for the soft rot bacteria, leading to soft rot and accelerating the death of the whole plant.
First, life habits
The worm has occurred for many generations a year, and the number of dynasties in China has gradually increased from north to south. Yunnan usually has 8 to 10 generations, and the algebras vary from place to place. Kunming has a mild climate, and cruciferous vegetables are available all year round. Therefore, cabbage caterpillars can be seen at any time, but in the late spring and early summer (April to June) and late autumn and early winter (September to November) twice. The climate in Yunnan is diverse. The cabbages in the localities are mostly wintering. The wintering places are mostly between the soil seams, weeds, trunks, fences or residual leaves in the autumn, and the environment is dry and the sun is not directly exposed.
The eggs are laid 2 to 3 days after the mating of the adults, and the egg period is 4 to 8 days. The larvae are 5 years old and the larval stage is 11 to 12 days. In addition to wintering for several months, it is usually 5 to 16 days. The adult life span is about 2 to 5 weeks.
Adults only live during the day and inhabit the densely grown plants at night. It usually starts after the morning dew is dry, especially at sunny noon, when they often appear in the flowers to suck flowers and lay eggs. When the adult lays eggs, it has a tendency to the mustard oil, and the mustard oil is unique to the cruciferous family. Therefore, the eggs are mostly produced on cruciferous vegetables, especially on the cabbage and broccoli, and the eggs are scattered. When an adult flies on a vegetable garden, it stops every time on the vegetable plant, that is, one egg is laid. Summer eggs are prolific on the back of the leaves, and in winter, they are prolific on the front of the leaves, and a few are produced on the petioles. Each female lays about 120 eggs on average, with more eggs in the wintering and first generation.
Eggs hatch in the early morning, and the first hatching insects eat the egg shells first, then feed the leaves. When the 2nd instar larva is frightened, there is a habit of falling silk, and the older larvae fall into the ground. The larvae move slowly, but the mature larvae can crawl farther. Go find a place to pour. More on the back of the leaf or on the front side of the leaf, before the pupation, the silk is wrapped around the leaves or the attachments, and then the silk is wrapped around the first section of the abdomen.
Occurrence conditions The cabbage caterpillar (the cabbage larvae) is suitable for development at 16 ° C ~ 31 ° C, relative humidity of 68% ~ 80%, the optimum temperature is 20 ° C ~ 25 ° C, the relative humidity is about 76%.
There are many natural enemies of cabbage caterpillars, such as golden wasps and broad-legged bees parasitized on the locusts; yellow velvet bees parasitic on larvae; large-eyed bees parasitized on eggs; and predatory hunting scorpions, Vespa; there are also parasitic bacteria, fungi, and viruses. The above natural enemies play a big role in suppressing insects.
Second, prevention measures
1. Clean the pastures After harvesting, remove the residual leaves in the field and burn them intensively to reduce the density of the insects.
2. Artificial capture It is easy to catch larvae and mites and adults. Adults can use net catching effects.
3. Protecting and utilizing natural enemy insects This method can prevent insects and protect the environment and reduce the pollution of pesticides.
4. Bio-pesticide prevention and control use 10 billion live spores/K. oxysporum wettable powder, spray 100-300 g per acre with 50-60 kg of water; or spray with 10 billion live spores/gram of green worm powder 1000 times; or use 100 The live spore/glucobacter WP can be added into the water to form 1000-1500 times liquid spray.
Any of the above medicinal agents can be sprayed at the initial stage of the pest, and sprayed once every 7 to 10 days, and can be continuously sprayed 2 to 3 times. The above biological pesticides can treat other moth butterfly pests on vegetables.
Jinnong Net
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