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Original title: Aphids are difficult to prevent, small vegetable moths are difficult to fight, how to control the two pests more effectively? (New method attached)
Mid-summer is a happy time for all kinds of pests, but vegetable farmers are very distressed by these pests, especially small vegetable moths and aphids, the former eats cabbage leaves and cabbage leaves full of holes, and the latter eats while discharging honeydew, and many vegetables are difficult to escape. Today, Xiaobian will share with you how these two pests can be prevented and controlled more effectively.
Aphids
1. What is Aphid?
Aphid refers to a group of aphids formed by the rapid proliferation of melon (cotton) aphids under the high temperature conditions of volta, which is small in size and yellow in color, so it is also called "yellow aphid". Compared with melon aphids in other periods, the aphids have the characteristics of fast reproduction speed, large incidence and great hazard of outbreaks.
Aphids occur mainly in July-August of each year. Volta aphids have a wide range of adaptation to temperature and humidity, and high temperatures and droughts are more conducive to the occurrence of aphids, with an average daily temperature of 24 °C to 27 °C, which can generally multiply a generation in 4 to 5 days, causing serious harm to crops such as cotton and melons.
2. Symptoms of aphid pest
The worm takes the sap from adults and nymphs on the leaf back and young stem of the host plant, and after the plant is damaged, the leaves shrink, the melon seedlings wilt, the old leaves turn yellow and fall early, and the melon aphids not only discharge a large amount of honeydew when they are infested, causing coal pollution diseases in the plants, but also spreading a variety of viral diseases.
3, figure to identify the two colors of melon aphids
▲Yellow type aphid
▲Black (green) color type aphid
4. How to prevent and control
1, you can use the strong tendency of aphids to yellow, hang yellow plates in the field to trap, at the same time, you can also lay insect-proof nets at the vent and doorway to block pests from entering the shed, carry out physical control, and the insect-proof nets should be no less than 60 mesh.
2, you can use heterochromatic ladybirds to prevent and control aphids.
3, natural enemy control can generally achieve a better control effect in the early stage of pest occurrence, when the insect population density is too large or the initial stage, it is necessary to apply chemical agents in time for prevention and control.
It can be fumigated with 10% promethane tobacco agent, 15% dichlorvos tobacco agent, 3% high-efficiency cypermethrin tobacco agent, 12% pyridoxine and isopropyl tobacco agent, and can also be controlled by spraying 5% acetamidine emulsion oil, 25% thiamethoxine water dispersible granules, 1.5% matrine solution agent and other drugs. Pay attention to the rotation of agents to reduce drug resistance.
New prevention and control methods
In addition, through the indoor virulence determination of melon aphids of different body colors, it was found that the sensitivity of the yellow type of melon aphid (aphid) to the insecticides imidacloprid and flufenidine was significantly lower than that of the black-green type, but there was no difference in the antibiotic agent - avermectin.
Further research showed that the difference in resistance between the two color types of melon aphids did not come from genetics and metabolism, but was related to the number of symbiotic bacteria in aphids - Bucknerella, and there were more symbiotic bacteria in yellow melon aphids than black and green types.
The latest research shows that the spraying of avermectin can significantly reduce the number of commensal bacteria in the aphids, so avermectin can be mixed with imidacloprid in the field, and experimental data show that it is 78% more effective than the use of imidacloprid alone.
Cabbage moth
Small cabbage moth, also known as a small green worm, two-headed pointed. The world's migratory pests are mainly cruciferous plants such as cabbage, purple cabbage, broccoli, cabbage, mustard greens, cauliflower, cabbage, rapeseed, radish and so on.
1, for the characteristics of harm
The young larvae burrow into the leaf flesh to feed, form transparent spots on the leaves, drill out the leaf flesh at the end of the first instar, and leave the epidermis at the leaf surface, and the 3-4 year old larvae can eat the vegetable leaves into holes and gaps, and in severe cases, the whole leaves are eaten into a network. At the seedling stage, the heart leaves are often concentrated as a pest, affecting the heart. On the remaining plants, it is harmful to young stems, young pods and grains.
▲Adult cabbage moth
▲Small cabbage moth eggs
▲Small cabbage moth larvae
▲The small vegetable moth pupates into cocoons
2. Life habits
There are two clear peaks of annual occurrence, the first from mid-May to late June and the second from late August to late October (during the large-scale cultivation of cruciferous vegetables). In general, autumn is more harmful than spring. The developmental temperature of the small cabbage moth is 20-30 ° C, and the first generation is completed in two peak periods for about 20 days.
3. Prevention and control methods
1. Agricultural prevention and control
Rational layout, try to avoid a large range of cruciferous vegetables annual continuous cropping, so as to avoid the recurrence of insect sources, strengthen management of seedling fields, timely prevention and control. After harvesting, it is necessary to deal with the dead leaves of the residual plant in time to eliminate a large number of insect sources.
2. Physical prevention and control
The cabbage moth has phototropism, and during the adult stage, black light lamps can be placed to trap the small cabbage moth to reduce the source of insects.
3. Biological control
There are many types of natural enemies of small cabbage moths, mainly predatory beetles, tiger beetles and spiders, parasitic wasps, cocoon bees and pathogenic microorganisms of bacteria, viruses and so on. These natural enemies should be protected when controlled by medication, and the first solution of 8000 IU/mg of Thuringiensis suspension 600 times and 2 billion PIB/ml of kale nuclear polyhedral virus suspension 600 times of liquid was used.
4. Pharmaceutical prevention and control
According to the results of experimental studies, the main pesticides recommended for alternating use are: 2.5% polycycline (Caixi) suspension 1000-2000 times liquid, 10% insect mite nitrile (exhaustion) suspension 1000-2000 times liquid, 15% indoxavir (ampere) suspension 3000 times liquid, 1% methylamino avermectin benzoate emulsion 2000-3000 times liquid, 1.8% avermectin emulsion 1500-2000 times liquid and 50% butetherurea suspension 1000-1500 times liquid.
Spraying should be even and meticulous, especially the back of the middle and lower leaves of kale is the main habitat of the young larvae of the small cabbage moth, and it should be sprayed on this part.
5. In the area where cruciferous vegetables are planted in large areas, small cabbage moth sex attractants or lost silk can be used for control.
Source: Vegetable pest prevention and control public welfare service platform
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