What are the countermeasures when planting vegetables and seedlings are met with insect pests?

Prevention of pests and diseases starts with seeds, which are the main source of viral infection. When we select seeds, we should choose the seeds of disease-free plants or use disease-free seedbed seedlings when raising seedlings, timely control of aphids, once aphids are found in the young leaves of seedlings, immediately spray with pymetrozine or imidacloprid; It can also be physically controlled with silver-gray film.

There is an optimal time to harvest each vegetable, and it is important to choose the right time to harvest. A few days late harvest will affect the quality, and it is easy to lead to the occurrence of pests and diseases. For example, peppers, timely harvesting can reduce the phenomenon of falling flowers, fruits and leaves.

In order to strengthen the prevention and control effect of pests and diseases, vegetable farmers should strictly comply with the relevant planting and production requirements of greenhouse vegetables, select high-quality seedlings, and at the same time should carry out large-scale irrigation before planting, and implement the disinfection and cleaning of greenhouse planting sites. Be prepared to enter the shed; Before sowing, the seeds and seedbed soil were disinfected with seed dressing and carbendazim to keep the seedbed soil loose, strengthen the management of ventilation, cooling and humidity drainage at the seedling stage, and spray 70% mancozeb 1000 2000 times or 70% methyl tobuzine 800 times solution at the beginning of the disease for control.

Vegetable seedling diseases are prone to frequent occurrences, and the main diseases are early blight, cataplexy, and blight. Therefore, by understanding the pathogenesis characteristics of these common diseases, production management can be targeted. Under suitable conditions, it only takes about 1 day from the onset of the disease to the seedlings, and the roots of the seedlings after cataplexy are dark brown, rotten and sunken, and then the water is lost and dried up.

Improper management of the nursery or seedbed, such as the use of old beds and unsterilized soil for seedlings, resulting in the accumulation of pathogens; The sowing is too dense, and the seedlings are not divided and interspersed in time. Water accumulation on the bed surface after irrigation; Poor thermal insulation performance of the nursery house, freezing or improper ventilation of seedlings will aggravate various seedling diseases.

Adequate application of nitrogen, phosphorus and potassium; sowing evenly; humidity regulation; Eliminate sick and weak seedlings in time. Carbendazim, methyl tobuzin, seed dressing, and dioxyl can also be used to disinfect the soil with the same amount of sodium disulfonate and zebin as the same amount. Soak seeds in constant temperature water, or disinfect with 1% saline, or soak seeds with multiple pesticides, and treat seeds with biocontrol agents.

There is also a type of medicine.

You can use plant-specific insecticides, evenly spray on the leaves of plants, do not water during the medication, otherwise it will reduce the efficacy, and scientific and reasonable fertilization and water supply are needed during the breeding period, which can effectively prevent plant diseases and pests.

<> the pests that harm the seedling stage of vegetables mainly include ground tigers, grubs, mole crickets, root maggots, etc.

The tiger mainly harms the seedlings of Solanaceae, Cucurbitaceae, Fabaceae and Cruciferous vegetables, and also feeds on a variety of weeds. The seedlings are bitten off from the base of the rhizome surface, or bite the seedlings cotyledons and young leaves, often causing the lack of seedlings, broken ridges or continuous death. The larvae can also burrow into the leaf bulbs of Solanaceae and Cucurbitaceae fruits, or cabbage, biting the fruits or leaf bulbs into cavities, and excreting feces inside, causing rot.

Grub is the common name of beetle larvae, commonly known as white soil silkworm, white ground silkworm, can harm eggplant fruits, melons, beans, leafy vegetables, etc. When feeding, the underground roots and stems of seedlings are bitten off, resulting in the death of the whole plant, and in severe cases, the lack of seedlings and broken ridges are caused. or gnaw on roots and tubers, weakening crop growth and affecting yield and quality.

The neat incision of the victim site is its hazard characteristic. Adults, also known as copper klang and blind bumper, can feed on the leaves, petals and shoots of a variety of plants.

Mole crickets, also known as lala crickets, soil dogs, etc., are omnivorous pests, and both adults and nymphs can be harmed. In addition to biting on freshly sown seeds (especially freshly sprouted seeds), young roots and young stems are also eaten in the soil. When drilling in the soil, the seedling roots can be cut off, and the tunnel often makes the seeds overhead or causes hanging roots, so that the seeds can not germinate or lose water and the orange dies, resulting in lack of seedlings and broken ridges.

The disorganized hemp of the damaged part of the rhizome is its identification characteristic.

Root maggots can harm a variety of vegetables. Harm seeds, feed on endosperm or cotyledons, cause bud rot, and fail to emerge; If the seedlings are harmed, they will be eaten upwards from the base of the rhizome, causing the plants to wither and die; If insects eat the adult plant, the plant will not grow well, causing the base of the rhizome to rot or die.

In mid-August, cauliflower is planted. Oily lettuce. The planting period of cabbage, as well as beans. Cucumber. Pea carob. Chives, etc.

The temperature and high temperature are variable, and the insect pests in the field are complicated, and the damage is more serious. In August, Spodoptera litura, Spodoptera exigua, bean borer, greenhouse vegetable whitefly and other diseases are in the outbreak period, in order to ensure the safe growth and development of vegetables and reduce the ease of use of biological pesticides, a variety of emerald green prevention and control measures can be selected to carry out prevention.

Spodoptera litura: Spodoptera liturae is produced all over the country in China, and it is a carnivorous insect pest, which is produced in Jiangxi in the Yangtze River section. Jiangsu.

Hunan. Hubei. Chekiang.

Anhui; Henan in the Yellow River section. Hebei. Shandong and other provinces.

It is very common to damage the host, and in addition to cruciferous vegetables, it can also damage melons. Eggplant. Beans.

Scallions. Amaranth. Broccoli and its food crops.

Crops and other nearly 100 families. More than 300 varieties of greenery.

The larvae bite the leaves. Flower bud. Flowers and fruits, the first instar larvae feed on the underbarkation and veins of the leaves, leaving only the outer skin with a fully transparent spot; After the 4th instar, they enter overeating, biting the leaves, leaving only the main vein.

On cabbage, the larvae can also burrow into the leaf bulb to injure the inside, empty the inside, and metabolize the excrement, resulting in environmental pollution, reducing or even losing the value of the commodity.

Prevention of agriculture and animal husbandry: the growth habit of feeding in clusters of young larvae is used, and when the larvae cluster is infested, the leaves are removed and the larvae are hunted by manpower. Look for the cocoons of the winter around the vegetable planting area and smash them.

Recruit larvae, dig cocoons to kill pupa after forming cocoons. Physical prevention: nymphs have strong phototropism, and insecticidal lamps are installed around the planting area to spray nymphs.

Spodoptera exigua: Spodoptera exigua, also known as Spodoptera exigua, is an omnivorous pest that damages vegetables. To shallots.

Cabbage. Cabbage. Lettuce.

Cauliflower. Carrot. Brown white.

Bracken. Capsule. Chaotian pepper.

Beans. Cauliflower. Green bean.

Chinese kale. Tomato. Small greens.

Vegetable. Broccoli. Broccoli.

Vegetables such as radishes are harmful. In more severe cases, the leaf veins can be eaten, leaving only the petioles, and even stripping the epidermis of the stem.

The larvae can be transferred in groups, slightly disturbed by the silk, and have the ability to deceive. 3??After 4 years of instar, it dives under the main stem or soil crevice in the daytime, and removes the feeding damage at dusk.

Produces 6??8 generations, 7??August produces a lot of high temperatures.

In drought years, there are a large number of people, often mixed with Spodoptera litura, which poses a great threat to leafy vegetables.

Prevention of agriculture and animal husbandry: autumn or winter ploughing, subsoiling of the soil layer, can solve part of the winter pupae; Spring 3-4 months to eliminate weeds, exterminate the first instar larvae on weeds; Eggs are collected by manpower, and the leaves of the hatched larval clusters are removed and transported centrally.

Pest control: maintenance using nemesis Spodoptera exigua, nemesis and various types of nemesis such as search engine spiders. Little frogs. Cabbage moths, biting wasps, etc. are crucial, and of course microbial nemesis manipulate the damage of Spodoptera exigua.

For example, cataplexy, blight, gray mold, blight, root disease, these diseases are very easy to appear.

For example, wilt, rust, blight, gray mold, leaf blight. These diseases are very likely.

Cataplexy , which is relatively common, occurs around the time of emergence and needs to be prevented in advance.

Some are caused by natural causes, such as when it rains a lot, the air humidity is relatively high, which is easy to breed bacteria, or it may be due to human factors, such as not replenishing fertilizer or water in time.

This is due to the fact that a lot of pesticides are produced in the process of planting, and it will also cause damage to the land, so these pests will be produced.

It is due to the unsuitable pH of the soil during the planting process, or the temperature and humidity are not suitable, or it may be that there are too few natural enemies.

Pollution-free vegetables are the common aspirations and requirements of many people, how to use pesticides rationally on vegetables, is the knowledge that many vegetable farmers need to know about the production of pollution-free vegetables. The basic principles of rational use of pesticides are science, safety, economic development and high efficiency. The specific description is as follows:

Methamidophos, hydroxyl 1605, dimethoate, carbofuran, etc. are highly toxic pesticides, DDT is a high residue pesticide, and the state stipulates that all high toxicity and high residue pesticides are not allowed to be used on vegetables. Every vegetable farmer must strictly implement it, which is also a must for safety.

1) Diseases and pests that can be controlled by non-organic chemical pesticide methods should be controlled with as little organic chemical pesticides as possible.

If Spodoptera liturae larvae have the habit of swarming, they can be manually removed or pinched to assist in control, so as to reduce drug control.

2) Manipulate the total area and frequency of pesticide application as much as possible. Those that can be treated are not universally treated, but those that can be treated at the same time (such as Spodoptera litura, Spodoptera exigua, diamondback moth can be treated, whiteflies and budworms can be treated, and sclerotinia and gray mold can be treated at the same time) are not treated alone, so as to reduce the number of drugs and maintain the nemesis.

Different pests and diseases react differently to pesticides. Similarly, different pesticides also have their own application fields, and the control goals of pesticides will also change with the emergence of resistance, so it is necessary to select the best pesticides according to the control objectives, pesticide performance and resistance level. In addition to having a good control effect on the control target, the selection of pesticides also needs to be safe and harmless to food crops.

Whether to use drugs and when to use them should be carried out in a timely manner according to the effects of different pesticides and insect pest habits and the growth stage that is easy to be poisoned and die in the process of production; When using pesticides, microbial pesticides should be preferred, and according to the amount of pests and diseases is not to achieve the control index value, but also need to take into account the climatic conditions, such as rainy days are not suitable for sprayers, in the morning before the dew is not suitable for sprayers, when the wind is strong and high temperature in the afternoon to stop spraying, diseases and small and medium-sized insect pests should generally produce early medication, noctuidae insect pests should be used at dusk, etc.

Long-term repeated use of the same pesticide for the prevention and control of a pest will definitely make the microorganism gradually improve its resistance to the agent, so that the control effect will be greatly reduced. At the same time, because there is interactive resistance, that is, a pest that has become resistant to a certain agent can also become resistant to some similar agents that have not been used, and then the effect of the drug is reduced. One of the most effective ways to get rid of and delay resistance is to rotate two pesticides with different mechanisms of action.