What should we do if pests and diseases occur during vegetable cultivation in greenhouses? The first thing most vegetable farmers think of is chemical pesticides, because the use of chemical pesticides for prevention and control is highly lethal and effective, but it has negative impacts on the ecological environment and human health. In recent years, vegetable pests and diseases in greenhouses have always been one of the main threats to vegetable production safety. The use of chemical agents to control them not only requires a large investment of manpower and material resources, but sometimes the control effects are not ideal. If scientific and reasonable prevention and control measures are taken before the occurrence of pests and diseases, the occurrence of pests and diseases can be controlled at a lower cost, and green prevention and control technology is one of everyone's first choices.
What is greenhouse green prevention and control technology?
Greenhouse green prevention and control refers to the limited use of agricultural ecological prevention and control in the greenhouse vegetable production process for the purpose of reducing chemical pesticides on the premise of ensuring the target yield and quality of vegetables and the safety of the vegetable field ecological environment. , physical control and biological control and other comprehensive technical measures to control the damage caused by pests and diseases. Agro-ecological prevention and control: In greenhouse vegetable production, the available agro-ecological prevention and control technical measures mainly include selecting disease-resistant varieties, scientific crop rotation, improving cultivation methods, cultivating healthy plants without diseases and pests, and creating a field ecological environment that is not conducive to the growth and development of pests and diseases. wait. Physical prevention and control: The purpose of preventing and controlling pests and diseases is mainly achieved through measures such as high-temperature stuffy sheds, adding insect-proof nets, and hanging color boards. Biological control: mainly the use of natural enemies, such as using insects to control insects, using mites to control mites, and using bacteria to control bacteria. Pesticide prevention and control: In terms of green prevention and control, pesticide use requires priority to use biological pesticides and some mineral-derived pesticides.
Common diseases and insect pests in greenhouse vegetable cultivation
There are many common diseases and insect pests in greenhouse vegetable cultivation, which are divided into underground and aboveground parts: Aboveground diseases: Fungal diseases include powdery mildew and downy mildew. , gray mold, leaf mold, etc.; bacterial diseases include bacterial angular spot, etc. and viral diseases. Underground soil-borne diseases: root-knot nematodes, fusarium wilt, and root rot.
Common pests in greenhouse vegetable cultivation include whiteflies, aphids, spider mites, thrips, and underground pests such as grubs and wireworms.
Green prevention and control of vegetable pests and diseases in greenhouses
How to greenly prevent and control pests and diseases in vegetable cultivation in greenhouses? First of all, we must choose disease and insect resistant varieties or disease and insect tolerant varieties, which is the most economical, effective and greenest method of pest control; secondly, we must choose strong seedlings that are disease-free and insect-free.
1. Select disease-free and strong seedlings
Green prevention and control of pests and diseases in greenhouse vegetable cultivation puts forward more stringent requirements for seedling greenhouses, seeds, substrates and seedling management.
1. Requirements for seedling greenhouses
It is best to use a dedicated greenhouse to avoid bringing pests and diseases during the production process into the seedlings. The vents of the greenhouse should include top air vents. The waist and waist air vents should be sealed with 40 to 60 mesh insect-proof netting, and an insect-proof net curtain should also be hung at the entrance to ensure that external lepidopteran pests, winged aphids, whiteflies and other migratory pests cannot enter the nursery greenhouse. Reduce sources of pests.
2. Seedling substrate requirements
When selecting a seedling substrate, it must be clean and free of germs. You can use unused peat and vermiculite, and use biological pesticides for sterilization. Such as Trichoderma harzianum or Pythium oligandrum.
3. Seed requirements
Ensure that the seeds are free from diseases and insect pests. The seeds need to be disinfected before sowing. Traditional physical methods can be used to soak seeds in warm soup. The specific method is: first soak the seeds in room temperature water for 15 minutes, then transfer the seeds to 55~60℃ hot water for soaking, stir continuously and maintain the water temperature for 10~15 minutes. At this temperature, Fungi and insect eggs carried on the surface or epidermis of the seeds are basically killed. Then let the water temperature drop to 30°C for soaking the seeds. In order to make the sterilization effect more thorough, you can use 10,000 times aqueous solution of oligoandropyromycin wettable powder when soaking the seeds.
4. Seedbed management requirements
Seedbed management after emergence must strictly control environmental conditions such as temperature, humidity, and light according to the growth requirements of each vegetable to reduce the occurrence of pests and diseases. Chance. At the same time, water and fertilizer management should be strengthened to promote the growth of seedlings and enhance their resistance to diseases and insect pests.
In terms of pest control, prevention should be strengthened. After the cotyledons expand, spray Pythium oligandrum wettable powder 10,000 times or Trichoderma harzianum wettable powder 1,500-3,000 times to prevent damping-off and other fungal diseases. Before transplanting, spray once on the leaves to further prevent harmful fungi and ensure that the seedlings are free of pathogens.
During vegetable seedling cultivation, insect pests generally rarely occur. Occasionally, aphids, whiteflies, thrips and other pests may occur. You can insert yellow boards on the greenhouse bed to trap aphids and whiteflies; insert blue boards to trap them. thrips. If it is found that the insect situation is on the rise, you can spray foliar pesticides such as 0.3% matrine 1000-1500 times, or 0.3% azadirachtin 150-200 times, or 95% mineral oil 150-200 times. twice the amount of liquid for prevention and treatment.
After the above-mentioned checks, strong, disease-free and pest-free seedlings will be cultivated.
2. Production greenhouse preparation
1. Pay attention to the stubble
Pay attention to the stubble to avoid repeated or continuous cropping. Because crops of the same type or family generally have similar diseases and pests, especially some soil-borne diseases and pests. If these pathogenic bacteria and pests are planted continuously, they will accumulate in the soil one after another, thus making the pests and diseases worse.
2. Install insect-proof nets
Insect-proof nets of 40 to 60 mesh should be installed at the ventilation openings of the greenhouse, including the entrance and exit doors. In addition, doing the following tasks will also help reduce the number of pests and diseases in the shed.
3. Clean the garden and deeply plow the land
Before soil preparation, the remaining plants and new weeds left by the previous crop should be cleaned up and taken out of the greenhouse. Because they are often a hiding place for germs and pests. The organic fertilizer used as base fertilizer must be completely decomposed. There are often a large number of pathogens and pests in unripe organic fertilizer. Another point is to pay attention to deep plowing of the soil, which is generally required to reach 25 to 30 centimeters. During the process of deep plowing of the soil, the living environment of underground pests and germs will be destroyed, and their numbers can also be effectively reduced.
4. Sterilization and pest control in greenhouses
In order to more thoroughly kill their germs and pests, disinfection of greenhouses and soil is essential. Here is what I would like to remind you. Yes, there are many methods for greenhouse disinfection, and we can choose the appropriate method according to our own conditions. Soil disinfection requires choosing the appropriate time. At present, the green prevention and control measures used in shed disinfection mainly include high-temperature stuffy sheds, ozone disinfection, sulfur fumigation and other methods.
(1) High-temperature greenhouse
Autumn and winter vegetables are usually planted in early September. You can choose a sunny time during the high temperature season of July to August before planting. Weather, the airtight greenhouse should be kept under high temperature. After 15 to 20 days, most of the germs and pests inside the shed and on the soil surface will be killed.
Winter and spring greenhouse vegetable production is generally planted at the end of February and early March, and the greenhouse time is from January to February. Due to the cold weather, it is not effective to stuff the greenhouse at high temperature before planting, and the greenhouse must be sterilized and insecticided. , Green prevention and control can use other disinfection methods, such as ozone, sulfur fumigation, etc.
(2) Ozone disinfection
Ozone is a colorless gas with a grassy smell. Its chemical molecular structure has one more active oxygen atom than oxygen molecules. Therefore, it has strong oxidizing properties. This oxidizing property has a killing effect on microorganisms such as bacteria, viruses, fungi and nematodes. Ozone is very unstable and can quickly reduce itself to oxygen in 30 minutes at room temperature. Oxygen is a beneficial gas needed by humans and other organisms. Therefore, it will not cause problems such as environmental pollution.
(3) Sulfur fumigation
Sulfur powder is a yellow powder substance extracted from natural ores. It has a distinct smell. Burning sulfur powder for fumigation and disinfection has good sterilization and disinfection effects. Insect effect. When using sulfur fumigation and disinfection, 2 to 3 kilograms of sulfur are needed per acre of greenhouse. It is also equipped with a certain proportion of flammable substances such as sawdust. Seal the greenhouse well, use an iron or ceramic tray as a container, put newspapers or sawdust underneath to help burn, put sulfur powder on top, place 6 points evenly in the greenhouse, after lighting the newspapers or sawdust, the sulfur will Under the action of high temperature, it begins to melt and release pungent sulfur dioxide gas. When sulfur dioxide meets water, it forms sulfurous acid. Sulfurous acid has an oxidative effect and can kill pests, germs and other harmful organisms on the surface of the greenhouse. After 1 to 2 days of airtight fumigation Ventilate. After 2 days of ventilation, the shed can be used.
In addition, if it is a plug-in sulfur fumigator, you only need to pour sulfur powder and plug it in.
(4) Soil disinfection
For greenhouses with serious soil-borne diseases, sunlight can also be used to directly conduct high-temperature soil disinfection. The best time to do this is in the midsummer season of July to August. It is best to pour some water on the plowed soil appropriately on a sunny day when the temperature exceeds 35°C to keep the soil at a certain humidity. Cover the ground surface with the discarded greenhouse film, and cover it with soil around it and compact it tightly. In this way, the top layer of soil is 15 cm. The soil temperature within the range can be raised to 55~70℃ and maintained for more than fifteen days. Under such high temperatures, most soil-borne diseases and pests such as root-knot nematodes, grubs, wireworms, and some bacteria are easily killed.
3. Green prevention and control after vegetable planting in greenhouses
After the previous work, the greenhouse with no or few pests and diseases is ready. However, just having a healthy growing environment is not enough. In the subsequent planting process, there is still a lot of green prevention and control work that needs to be done.
1. Green prevention and control of pests
(1) Hanging color boards
Hang yellow boards and blue boards as early as possible. This is the same as when raising seedlings. The purpose is also to trap aphids, whiteflies and thrips. 30 25cm x 30cm color plates need to be evenly distributed and hung per acre of greenhouse. The hanging height is required to be 10 to 15 cm above the growth point of the plant, and the height should be continuously increased as the plant grows.
(2) Use natural enemies to control pests
Use the natural enemies of pests to control pests, such as the natural enemies of aphids, aphid braconids, ladybugs, etc., but the number of naturally occurring natural enemies in the greenhouse It is relatively small and cannot control pests, so artificial supplementary release is required.
① Ladybugs protect against aphids
Ladybugs belong to the order Coleoptera and Coccinellidae. The ladybugs used in production are mainly Coccinella axyridis and Coccinella septempuncata. To use ladybugs to control aphids, you can release ladybug adults, larvae or eggs in the greenhouse, usually in the early stages of aphids. In this way, a small number of ladybugs can control the damage of aphids.
When releasing, place the ladybugs in a shallow container next to the plant where aphids are concentrated, and hang the egg card directly on the middle and lower part of the plant. The eggs usually hatch into larvae in 2 days, and the quantity released is based on the benefit-to-harm ratio of ladybugs and aphids, which is 1:40~1:60. The best time to release is before 10 a.m. and after 5 p.m. when the temperature in the shed is relatively low. This will help improve the survival rate of ladybugs in the greenhouse. In addition, it should be noted that the use of chemical pesticides is strictly prohibited one week before release and during the prevention and control period.
②The Aphidid wasp prevents whiteflies
The Aphidid wasp is very small, about 0.6 mm, and belongs to the order Hymenoptera, Aphididae, and the genus Aphididae. . The wasp is the natural enemy of whiteflies. It can lay eggs in the body of whitefly nymphs and develop into adults there, turning the nymphs into black pupae and unable to continue development. The release of callipids should be carried out immediately when whiteflies appear in the greenhouse. Hang the pupae of callipids on the side branches of the plants. After 1 to 2 days, the callipids will begin to break their shells one after another and then erode. Planthopper nymphs. To release the bees, it is generally required to hang 50 pupae cards per acre of greenhouse at one time to ensure that about 10,000 bees can be released. It is usually released every 7 to 10 days and released 3 to 5 times continuously.
③Predatory mites protect against spider mites and thrips
Predatory mites are nocturnal mites that feed on spider mites and other insects. Compared with spider mites, predatory mites do not have an advantage in size, but they move quickly and have scissor-like mouthparts, which can easily defeat spider mites. The release of predatory mites should be carried out in the early stages of spider mite occurrence. In the early stages of vegetable growth, just place the torn predatory mite bags directly next to the plants. Generally, 70 to 100 bags per acre of greenhouse are needed at a time. To release it during the middle and late stages of vegetable growth, the torn bag can be hung on the branches in the middle of the plant, or it can be sprinkled directly on the leaves. In addition, predatory mites can also be used to control thrips at the same time, in the same way as spider mites.
④Biological pesticide control
If the number of pests in the field is relatively large, biopesticides such as matrine aqueous solution or azadirachtin EC need to be used before releasing natural enemies, and should be sprayed on the leaves first. Once, reduce the insect population density and release natural enemies one week later.
⑤Chemical pesticide control
If the pest population density is not reduced during the release of natural enemies, and there is a large increase, chemical pesticides can be used for rapid control. Reduce the insect population density, release additional natural enemies after 15 days, and continue to use natural enemies for control. When choosing chemical pesticides, you should choose some high-efficiency and low-toxic pesticides that are less harmful to natural enemies. For example, you can use pymetrozine to treat aphids and thrips, which is almost harmless to ladybugs; you can use fluflubenzuron to treat spider mites, which is harmless to predatory mites. These pesticides must be used strictly in accordance with the product instructions.
2. Green prevention and control of diseases
To achieve green prevention and control of vegetable diseases in greenhouses, prevention and comprehensive prevention and control are the key.
(1) Adopt scientific and reasonable cultivation methods
Adopt scientific and reasonable cultivation methods to ensure that vegetables grow in the most suitable environment and are as susceptible to disease erosion as possible. For example, during the cultivation process, the use of film-covered small high ridge drip irrigation cultivation not only saves water and is easy to manage, but the film covering the surface can prevent the water in the soil from evaporating into the environment and prevent the relative humidity of the air in the shed from being too high, thus effectively Reduce the occurrence of high-humidity fungal diseases such as powdery mildew, gray mold, leaf mold, downy mildew, etc.
(2) Strengthen cultivation and management
It is necessary to strengthen cultivation and management, cultivate strong plants, so that the plants themselves have strong disease resistance, and at the same time, create an environment that is not conducive to the occurrence of diseases. condition. In terms of temperature management, it is necessary to ensure that vegetables are in a more suitable temperature range at different growth stages to enable them to grow healthily; in fertilizer and water management, watering and formula fertilization should be carried out according to the growth characteristics of various vegetables to meet the growth needs of plants at each stage. Required; in humidity management, pay attention to ventilation and dehumidification, and maintain an appropriately low relative air humidity, generally not exceeding 50%.
In addition, maintain a reasonable density in the field, remove old and yellow leaves in the lower part of the plant as early as possible, and enhance the ventilation and light transmittance of the lower part of the plant. Do not place the disease between the greenhouse where the disease is more serious and the disease is less severe. Frequent operations such as back and forth can also effectively prevent diseases.
(3) Regular spraying of biological pesticides
Regular spraying of protective biological pesticides can also prevent diseases. For example, spraying Pythium oligandrum or Trichoderma harzianum on the leaves every 15 days after two weeks of planting can prevent powdery mildew, gray mold, downy mildew, leaf mold and other fungal diseases. Foliar spraying of ningnanmycin can prevent viral diseases.
If a disease occurs in the field, green control must be carried out in the early stages of the disease, and biopesticides are still the first choice. To control gray mold and leaf mold, Trichomycin harzianum or Pythium oligandrum can be used; to control powdery mildew, Ningnanmycin can be used; to control downy mildew, matrine or Pythium oligandrum can be used; to control viral diseases, Pythium oligandrum can be used. Ningnanmycin; agricultural streptomycin can be used to prevent bacterial angular leaf spot; Bacillus licheniformis or agricultural antibiotic 120 can be used to irrigate roots with drip irrigation to prevent and treat fusarium wilt of melons and vegetables. The specific usage of each of the above pharmaceuticals can be carried out in accordance with the product instructions or under the guidance of professionals.
Severe diseased leaves should be removed as soon as possible, and the blighted plants should be uprooted and taken out of the greenhouse. These measures can also effectively reduce the disease. For some low-temperature fungal diseases, such as gray mold, downy mildew, leaf mold, etc., high-temperature shelter methods can also be used to prevent and control them. High-temperature stuffy sheds have very strict technical operation requirements. Improper operation will not achieve the expected purpose. Moreover, different vegetables have different tolerances to high temperatures, so they need to be carried out under the guidance of professional technicians.
(4) Chemical pesticide control
If the disease develops quickly in the field, some diseases can be sprayed with chemical pesticides to quickly reduce the number of pathogenic bacteria in the field. To prevent and control powdery mildew, polyantimycin, A Base thiophanate, triazoles, and thiophanate; carbendazim and thiophanate methyl can be used to control gray mold; metalaxyl and chlorothalonil can be used to control downy mildew; chlorothalonil and chlorothalonil can be used to control leaf mold. Mili et al. Carry out foliar spraying, and the specific usage method should strictly follow the product instructions or be carried out under the guidance of professionals.
The application of green prevention and control technology for vegetable pests and diseases in greenhouses can greatly improve the edible value and commercial value of vegetables while reducing the amount of chemical pesticides. I believe this technology will be more and more popular. It is favored by vegetable farmer friends and helps everyone increase efficiency and generate income.