For a long time, the prevention and control of whitefly is a headache for vegetable farmers.
Recently, the vegetable farmers have said that the white peony in the greenhouse and the open field has already become a disaster. Just after taking the medicine, it has not been very good for two days. It has not been used for several times, or it is not dead, or it has a short duration. The insects are more and more difficult to fight, and the insects are so difficult to cure. The law can achieve better decontamination effects.
What causes the white mites to become more and more harmful and difficult to treat?
Whitefly, also known as the white moth, is a sucking pest and is a worldwide pest. Spring occurs in the greenhouse, from mid-April to late-May; autumn occurs in greenhouses, cold sheds, open fields and other facilities, from the end of July to the end of September, the greenhouse will continue until the end of November.
Generally, adults and nymphs like to cluster on the back of plant leaves, so that the sucking mouth can absorb the plant juice, so that the damaged leaves are chlorotic, yellow, wilting, and even the whole plant is dead.
Adults will be excreted, and excreta will seriously affect the fruit surface or leaf surface of the fruit, causing diseases such as coal pollution.
And it also spreads a lot of viruses, causing other diseases to occur. According to years of observation and summary, the main reasons for the refractory pests are as follows.
The cause of refractory white powder
2.1 The reasons for the whitefly itself
1 a wide range of hosts
This pest is easy to occur in both protected areas and open fields. A variety of crops are also common in various places, which can damage more than 600 plants in 112 families. Most of the crops are â€œvegetablesâ€, regardless of whether they are in the greenhouse all year round. The open field is the ideal place to live and breed.
2 super breeding ability
In the greenhouse, whitefly mites occur more than 10 generations a year, overlapping generations, and the development time of each generation is shortened with the increase of temperature. Under the condition of suitable conditions, 100 eggs per spawning of each whitefly, calculated after 10 generations. The number of exponential growth is simply astronomical.
3 plants on the insect state is more mixed, not good prevention
General medicine can only kill adult worms, it is difficult to kill eggs and larvae, the number of medications can not keep up with the speed of reproduction, resulting in more difficult to treat.
4 adult factors
The wing surface is covered with white wax powder, which is not easy to bond with liquid medicine. When the temperature is low in the morning, the flight ability is weak. When the sun is out and the temperature is high, the flight ability is strong.
5 human factors
In recent years, with frequent application of drugs, its resistance has gradually increased, becoming more stubborn and refractory.
2.2 Misunderstandings in human control
1 Prevention and treatment awareness is weak, re-treatment and light defense
Some vegetable farmers have a weak sense of using the insect-proof net in advance, and there is a hole that does not make up, and there is a gap between the gaps. Even after finding the whitefly, the insect-repellent net is used, which is very bad for controlling the whitefly.
2 failed to achieve group defense
Due to the strong migration of whitefly, in the vegetable growing area, only one drug is used for prevention and treatment, and other families are not cured. After the drug is used, the pest will soon return.
3 failed to continue medication
When the medicine is used, some of the pests will escape. After the medicine is used, they will come back and continue to be harmful. After a few days, they will be flooded. If you can take it again the next day, the insecticidal effect is very obvious after two passes.
4 The quality of application is not high
Many farmers use the medicine to save trouble. They only want to spray an acre of land with a spray of water. Often, the medicament is not sprayed with insects at all, and even the leaves are not wet. Or just spray the front of the blade, ignoring the eggs on the back of the blade.
5 medication time is not suitable
When the temperature is high at noon or afternoon, the whitefly flies fast, and the whitefly is flying away. It is impossible to hit the insects. After you finish the medicine, it will continue to come back.
6 Pharmacy selection problem
Some medicinal agents only kill adult worms and do not kill eggs, resulting in continuous insects after hatching. Then this kind of "grass does not remove the roots, the insects do not kill the eggs" approach allows the pests to gradually develop resistance during the breeding process.
7 I don't know the combination of smoked and sprayed drugs.
Most farmers do not know the way smokers are combined with sprays, nor do they understand the effects of combined use.
3.1 Rotation of the crop, eradicate the source of insects
In the area where the whitefly mites occur, the open-season vegetables in the shed or the shed around the shed should be selected from celery, spinach, garlic, leeks, sage, rape and other white glutinous vegetables that are not suitable for food and low temperature. The hazard can also prevent the spread to the shed.
Clean up the residual leaves and weeds in time after harvesting each crop to reduce its lodging place. During the summer off-season period, high temperature shacks can be carried out, which can effectively eliminate the white mites in the shed.
Use a fumigant to smother the pests before sowing the vegetables. An insect-repellent net is set on the seedbed or in the greenhouse vent to prevent foreign insects from moving in.
3.2 trapping and avoiding and biological control
For the production of organic vegetables, the use of insecticides is prohibited. The whitefly can be used to have a strong tendency to yellow. Yellow fungus boards are suspended 15cm above the crops in the greenhouse to trap adults.
Or use biological control. When the average adult of whitefly mites in the greenhouse has 0.5-1 heads per plant, the artificially propagated larvae are released, and each adult or pupa 3-5 heads are placed once every 10 days. Put a total of 4 times. It can also be artificially released, and a grasshopper can prey on more than 170 larvae of whitefly.
3.3 Change the misunderstanding of medication
1 Adhere to group prevention and treatment, continuous medication
For example, when it is used to control the whitefly of the contiguous vegetable base, it is best to use it once a day, and then use the medicine again the next day.
2 Choose insecticide and ovicide to use synergist
According to Bemisia tabaci and whitefly, the adults are active, while the eggs are mainly concentrated in the living habits of the middle and lower leaves. Adjust the time of administration, choose to use the medicine when the whitefly is flying slowly in the morning or at night, and focus on spraying the middle and lower leaves to kill the eggs.
3 Ensure adequate dosage
According to the wet leaf surface, both sides of the blade are sprayed on the front and back sides. It is recommended to use the mist sprayer to apply the medicine, which not only saves labor and time, but also sprays the medicine comprehensively, but it is necessary to know whether the medicine is resistant to high temperature.
4 adhere to the combination of smoke and spray
Take the night with 10% smoke to win the smoked smog, the insecticide does not leave a dead end, and the next morning, spray the insecticide and ovicidal agent.
It is recommended that pesticides that kill eggs be used in combination with agents that kill adults, which can fundamentally control the number of pests and have a long-lasting effect. It is more effective to add a vegetable oil adjuvant to the above-mentioned medicament.
Because the whitefly is extremely resistant to drug resistance, the control agents should be used interchangeably to avoid drug resistance.
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