In the spring, with the gradual recovery of temperature, "small insects" such as aphids, whiteflies, mites, and thrips in the greenhouse enter a rapid breeding period. These "small insects" have a large population density, overlapping generations, small insects are difficult to find, drug resistance is increasing year by year, if not timely symptomatic prevention or treatment, it is easy to cause pest flooding, seriously reduce vegetable production, affect economic benefits.
1. Harmful symptoms
1. Aphids
There are many kinds of aphids, including peach aphids, cotton aphids, melon aphids, radish aphids and so on. Almost all vegetable crops can be used as host plants, but mainly melons, solanum, cruciferous vegetables. Aphids are pests of sucking mouthparts, in which adult or nymph swarms gather on the back of leaves, or suck sap from growth points such as young stems and shoots.
Aphids are directly infested only by taking sap from their mouthparts, and the secreted honeydew drops on the lower leaves, causing mycosis to occur, hindering leaf physiological functions, and reducing the accumulation of dry matter in the plant. Aphids also transmit viral diseases, causing greater harm.
From March onwards, as temperatures rise, aphids begin to become infested crops, peaking in mid-April to early to mid-June, and peaking in late August to early November in the second half of the year.
2. Whitefly
Whitefly-like pests can be pested in sheds all year round. Common whiteflies mainly include whitefly and greenhouse whitefly. Adults and nymphs cluster on the back of the leaves, pierce the leaf flesh with a suction mouthpiece, and suck up the sap of the plant, causing the leaves to fade, turn yellow, wilt, or even die in the whole plant.
The fruit is deformed and rigid, causing premature plant aging and affecting yield. Strong fecundity, fast reproduction speed of whitefly, large population, cluster harm, can secrete a large amount of honey, serious pollution of leaves and fruits, often cause a large occurrence of coal pollution disease, so that vegetables lose their commercial value.
Adults prefer windless warm weather and are yellowish. Adult whitefly are clustered on the back of the leaves and are tender, so there are many new leaves in the upper part of the plant. The unhatched eggs are mainly concentrated in the back of the leaves and side branches in the middle layer and above of the plant, and most of the eggs on the old leaves below the middle layer have hatched. Therefore, there should be some emphasis when spraying.
3. Thrips
Thrips are more common in the production of eggplant, peppers and melon vegetables. All parts of the leaf can be damaged, but the leaf back is the main one; adults and nymphs file to suck plant growth points and flower vessels. At the seedling stage, thrips are generally clustered on the back of the leaves for pests, and when the damage is serious, they are connected into pieces, which can cause the leaves to become hard, shrink, slender, and wrinkled, and the top leaves cannot be unfolded, forming a "rabbit ear shape", the plant growth is slow, the internodes are shortened, and the virus disease hazard is suspected. The leaves of the melon are grayish brown or black-brown, the flowers are infertile or fruity, the young pods are damaged, and silver feeding scars can be seen.
Thrips peak in autumn or winter in November-December, and March-May is the second peak. Thrips prefer warm, arid environments, and the suitable temperature for growth is 23 °C-28 °C, and the suitable humidity is 40%-70%. The humidity is too high to survive, and when the humidity reaches 100% and the temperature reaches 31 ° C, all the nymphs die.
During the rainy season, if the weather is cloudy and rainy, it can cause the death of nymphs. After heavy rain or watering, the soil compacts, so that the nymphs cannot enter the soil to pupate, and the pupae cannot hatch into adults. Adult insects are active, flying, and photophobic, mostly in the leaf back or soil crevices during the day, cloudy, morning, evening and night only on the surface of the host, which brings great difficulties to the control of thrips. Spraying time is best to choose early morning dew when the dew is not dry or near the evening.
4. Mites
Mites are extremely harmful to vegetables such as peppers, eggplants, and loofahs. Mite pests include red spiders, tea yellow mites and so on. Red spiders can see needle-tip-sized red dots on the back of the leaves, with adult mites or mites clustering into orange-red to bright red insect piles as the back of the leaf. The front and back of the affected leaf correspond to the small white dots in the harmed area, or the greening is irregularly yellowed.
In the middle and late stages, the whole plant seems to have symptoms of nitrogen deficiency and yellowing, and the front of the leaves of eggplant and tomato in the middle and late stages is covered with green spots, and the leaf veins are more obvious, like magnesium deficiency. When the pest mite occurs severely, the back of the leaf becomes sand spots, yellow-red, resulting in small leaves, green and yellow, and then dies, and there is a white wire mesh on the back, affecting the photosynthesis of the leaves. In the young parts of the plant, the growth point sucks the sap, causing baldness. Fine small white dots can be seen to harm the fruit or stem, and later it is wood-thrombotic.
When the leaves are damaged by the tea mite, the young leaves are crumpled, longitudinally rolled and become smaller, the leaves thicken, stiff, and fragile, and the leaf veins are twisted. The leaves are green on the front and yellowish-white to yellowish brown on the back, rough, shiny, oily or oil-soaked (different from viral diseases), and the leaves are narrow, wrinkled or twisted, browning or curling from the leaf margins (different from viral diseases). Pests are difficult to see with the naked eye.
Mites can occur almost all year round under shed conditions, and occur severely in spring and autumn. Mostly distributed on the back of the leaf, the normal spraying method of the liquid is mostly concentrated on the front of the leaf, the insecticidal effect is poor. Therefore, when spraying mite-killing agents, the sprayer nozzle should be tilted up by 45 degrees.
Second, prevention and control methods
1. Control of aphids
(1) To prevent insect pests in advance, it is recommended that fine methylacenetrile + thiamethoxam 1000 times liquid root irrigation;
(2) Strong reproductive ability, spread viral diseases, relatively hidden, and the spraying should be meticulous and thoughtful;
(3) At the beginning of the disease, spray with 3% acetamidine 1000 times liquid or 10% fludaramide -3000 times liquid or 25% prayadone 1500 times liquid + jiamei gold point 1000 times liquid; alternately, once every 7-8 days;
(4) Laying silver-gray film on furrow ridges can play a evasive role for aphids;
(5) If conditions permit, it is recommended to combine the medicinal smoking shed, foliar spray and hanging yellow armyworm board.
2. Prevention and control of whiteflies
Prevention and control program: Most of the current spray insecticides are mainly touch killing, and a few pesticides have both fumigation and food refusal effects. Whitefly cling to the leaf back to suck the sap of the leaves, which is easy to form a dead angle that pesticides cannot reach, especially in the case of lush plant growth. Moreover, when the whitefly is alarmed, it will fly to avoid, so that the touch killing effect of the liquid medicine is significantly reduced. Therefore, once the whitefly breaks out, it is difficult to rely on spraying alone to play a good prevention and control effect. Since the growth and development and reproduction of whiteflies are also very closely related to temperature, spraying combined with temperature or spraying should be adopted.
Temperature control method: the vent can be closed to ensure that the temperature in the shed is 1-2 hours at 30-33 ° C (it should be noted that the temperature should not be too high, and the time should not be too long, otherwise it is easy to produce drug damage), which can effectively improve the efficacy of pesticides and play a better control effect.
Vegetable farmer experience: Early stage: cavity application of insect repellent + other crops attraction + spray control
First, an aspirant agent is applied to the pit before colonization. For vegetable species that are susceptible to viruses, such as tomatoes and watermelons, insect control should start from seedling colonization. Because after the colonization of vegetables, especially after the colonization of autumn stubble vegetables, it is the period when the whitefly is seriously harmful, and only by starting from before colonization can we avoid the large number of whiteflies and spread the virus. Now, there are many agents that can be applied in the market, such as biological bacterioplastic preparations, tablet pesticides with sustained release ingredients, etc., which can play a good role in deworming. There is no special cave deworming product, and some vegetable farmers choose thiamethoxine + pyrimid ester to drizzle the roots, which also plays a good role at the beginning of colonization.
Second, plant some "food" that whiteflies like between the rows to focus on prevention and control. After the hole application, even if there are whiteflies in the shed, they do not like to eat on the colonized vegetables, if you plant some "food" that does not have a hole application agent or the whitefly on the back wall of the shed, such as melon, tomatoes, kidney beans, etc., you can better observe the occurrence of whitefly, so as to use the medicine as soon as possible to control the whitefly before the outbreak.
Third, viral diseases and whiteflies are suitable for growth under neutral or alkaline conditions. After spraying jiamei coin or vinegar liquid, the surface of the plant is acidic, which can inhibit or kill the bacteria and insect pests that do not like acidic conditions. After colonization, use Jiamei to spray once every 5-7 days, and spray 3-4 times continuously, which can effectively prevent and control viral diseases and increase production by more than 30%. In addition, it is necessary to pay attention to the timely supplementation of organic activation package nutrition Jiamei dividend, Hynpo, which has been studied and studied to be closely related to the lack of iron, zinc, calcium and other elements.
Later stage: armyworm plate + spraying
When the plant is larger and the effect of burrowing agents is not obvious, the whitefly can live in a larger space and the difficulty of spray control is greater.
Whitefly have a strong tendency to yellow, and yellow armyworm plates can be set up in greenhouses to trap adult insects. Yellow plates can be purchased directly from the market or made in-house. Paint the cardboard yellow with paint, put on a transparent plastic bag, apply a layer of sticky oil (mix well with no. 10 oil and a little butter), and reapply the sticky oil every 10 days. Yellow plates can trap adult insects, but are more important in providing monitoring of the occurrence of whiteflies. The armyworm board can be suspended above the plant, and the bottom of the yellow plate is flat or slightly higher than the top of the plant, 40-50 pieces per acre. When an increase in whiteflies is found, spray the drug in time.
To prevent insect pests in advance, it is recommended that fine methylpyrropyrronitrile + thiamethoxam multiply root irrigation, while spraying, optional 99% mineral oil emulsion 200-300 times liquid or 3% acetamidine emulsion 1500-2000 times liquid, 25% pyrazinone suspension 2500-4000 times liquid, 25% thiazide hydrable powder 2500 times liquid, 10% imidacloprid wettable powder 1000 times liquid, 1.8% avermectin emulsion 2000 times liquid, 1% methyl vitamin emulsion 2000 times liquid, 25% thiamethoxine water dispersible granules 3000-4000 times liquid, 0.3% neem emulsion 1000 times liquid, 25% thiamethoxine water dispersible granules 3000 times liquid. Spray the front and back of the leaves evenly, rotate the medication, and avoid the rapid development of resistance from whitefly.
3. Prevention and control of thrips
Control program: First, control is carried out according to the characteristics of thrips.
According to the characteristics of thrips breeding quickly and are prone to disasters, prevention should be the mainstay and comprehensive prevention and control should be carried out. For example, nutrient soil is used to raise seedlings and remove diseased leaves from residual plants. Frequent watering can eliminate nymphs and pupae in the ground. In addition, frequent weeding can reduce the harm. Can be booby-trapped using the blue plate. During the thrips period, spray the drug in the early morning when the dew is not dry or in the evening, focusing on the parts of plants where the thrips are easily moved. Optional 2.5% polyclidide water emulsion 70-100 g/l 60 l spray or 10% thiamethiasis water dispersible granules 5000-6000 times liquid, 24% spironium ethyl ester suspension 3500 times liquid, 15% zolomonamide emulsion 1100 times liquid, 40% acetamidine water dispersible granules 4000-6000 times liquid, 6% ethyl polycycline suspension 1000 times liquid, 24.5% high efficiency permethrin · thiamethiasis mixture 2000 times liquid,
4.5% high performance cypermethrin emulsion 2000 times liquid, 1.8% avermectin emulsion 2500-3000 times liquid, 2% methylamino avermectin benzoate emulsion 2000 times liquid, 10% alenopherol water agent 1500-2000 times liquid, 2.5% bifenthrin emulsion 2500 times liquid, 10% imidacloprid wettable powder 1000 times liquid, 10% flufenamidamide water dispersible granules 3000-4000 times liquid, 10% pyromeothrin emulsion 3000-4000 times liquid· Imidacloprid suspension agent 1500-2000 times liquid and other + Jiamei point 1000 times liquid spray control. Spray once every 5-7 days, 3-4 times continuously.
Second, pay attention to the time of medication. In production, many vegetable farmers reflect that thrips are difficult to treat and are harmful. When communicating with vegetable farmers about thrips prevention and control, Xiaobian found that thrips are difficult to treat, not because the medicine is not the right way, but because the medication time is not appropriate. Thrips have flowering properties, so the effect of pre-flowering medication is good, if you wait until a large number of flowering periods and then use drugs, thrips hide in the flowers, the prevention and control effect is poor. From the beginning of the flowering before the use of drugs to control, you can use avermectin, caixi and other agents, and then each spray should be mixed with avermectin, comprehensively prevent the occurrence of thrips. At the same time, the thrips also have the habit of lying down and sleeping at night, and the choice of daytime and morning medication is bound to be poor; therefore, in the prevention and control, the morning spray should also be changed to afternoon or evening.
Medication should pay attention to spraying and smoking combination. Simply spraying medicine, even the best mist-filling apparatus will have omissions, and thrips that have not sprayed medicine will flood. Therefore, when taking drugs, a combination of spraying and smoking can be used for prevention and treatment. Spray: foliar spray of Aerother, Longshi, smoking: smoking aphid tobacco or imidacloprid tobacco. However, it should be noted that the medication time should not be carried out in the morning or noon, and should be closed in the evening before closing.
4. Control of mites
Pharmaceutical control: 5% fipronea emulsion 1000-2000 times liquid or 50% butyl etherurea suspension 1000-1500 times liquid, 2.5% bifenthrin emulsion 3000 times liquid, 1% avermectin emulsion 2500-3000 times liquid, 73% alkyne mite emulsion 2000-2500 times liquid, 100 g/ liter insect mite suspension 600-800 times liquid, 15% sim avermectin emulsion 1000-1200 times liquid, 3.3% Avi · Biphenyl emulsion 1000-1500 times liquid, 10% Liuyangmycin emulsion 1000-1500 times liquid, 5% thiamethoxone emulsion 1500-2500 times liquid, 15% pyridoxine emulsion 1500-2000 times liquid, 5% azole ester suspension 2000-3000 times liquid, 10% imidacloprid wettable powder 1500 times liquid, 3% methyl vitamin salt emulsion 5500 times liquid and other spray prevention and treatment. Spray 1 time in 7-10 days, a total of 2-3 sprays.
Vegetable farmer experience 1: control mites "three steps"
Xiaobian saw a lot of greenhouse eggplant leaves dry and lifeless when visiting, vegetable farmers reflected that mites are too harmful, sprayed several times the drug, recently sprayed too much caused, but the insect control effect is not obvious. However, Master Zhao's eggplant has almost no mites as a pest, according to Master Zhao, if you want to better control mites, you have to go in three steps.
Step 1: Eliminate the source of insects. Dead leaves and weeds in the shed are the habitat of pests, so the first step in the prevention and control of mite pests is to eradicate the weeds in the shed in time, remove the dead branches and leaves, and cut off the source of infection.
Step 2: Temperature difference control mites. If the harm of mites in the shed is heavy, the breeding of mite pests can be prevented by adjusting the temperature in the shed (artificially created temperature difference). The daytime temperature can be increased to 32-35 ° C, maintained for more than two hours, and the nighttime temperature is maintained at 11-13 ° C to inhibit the reproduction of mites.
Step 3: Pharmaceutical control. Optional 1.8% avermectin emulsion 3000 times liquid or 15% pyridoxine emulsion 3000 times liquid, 20% dipramidone wettable powder 3000 times liquid, alternate rotation, improve the effectiveness. However, it should be noted that mites are not only tender, but also easy to concentrate on the back of the leaves, so the leaf back is the focus when spraying. When spraying the acaricide, spray up and down, pay attention to the young parts, turn over the nozzle and spray the back of the leaf upwards.
Vegetable farmer experience 2: suppress mites with mites
Predatory mites, especially like to prey on pest mites, sheds to raise it can be very good to deal with shed pest mites and whiteflies. Master Shouguang Li, who has been raising mites for a year, said: "Since I raised this predator mite (courgette blunt mite), this year I have not sprayed insecticides, saving both labor and money, and also producing high-quality vegetables." ”
In contrast, chemical pesticides can only exert their effectiveness for a short period of time, and once the effect is over, the mites may begin a new round of reproduction and ravages. The use of this method of "treating mites with mites" to control the pest of mites is not only good and low cost, but also very in line with the requirements of standardized production.
3. Precautions
Select some agents with better prevention and control effects, you can regularly spray helix ethyl ester, ethyl polybactericide, imidacloprid, furazine, thiamethoxine, etc., to avoid large-scale outbreaks of insect pests. At the same time, in the prevention and control of insect pests, attention should be paid to the following aspects:
1. Insecticides are used with egg killers to achieve both insect and egg killing. For example, adult insects, nymphs, eggs, etc. of whitefly exist at the same time in the shed, if only insects are killed, and eggs and pupae will continue to hatch into adult insects, will continue to be harmful to vegetables. To ensure the effectiveness of prevention and control, attention must be paid to the killing of insects and eggs.
For the control of mites, you can choose thiazole mite nitrile + pyridine + spirene ester + carmget point spray; control of thrips, you can choose polymycin + bifenthrin + jiamei point spray; control of whiteflies, you can choose thiazideone + alenidine spray; control of butterfly moth pests, you can choose Bacillus thuringiensis + mevin salt / flufenomidamide + fluridinyl urea + spray.
2. Insecticides are used with auxiliaries, such as sugar, penetrants, viscosants, etc. to improve the efficacy.
3. When taking drugs, combine the habits of pests. For example, thrips lie diurnal and nocturnal, and whiteflies, aphids, etc. lay eggs on the back of the leaves, which requires choosing the appropriate medication time and method.
4. The drug needs to be combined with fast-acting and long-acting effect. Pests breed in the shed for generations, after killing insects, the eggs will hatch, so when killing insects, you should pay attention to the quick-acting and long-acting collection to ensure a long period of effectiveness.
5. The key to the prevention and control of pests is the comprehensive use of drugs in the shed, including the ground and the shed, and at the same time, it is necessary to remove weeds around the shed and outside the shed at any time, build the insect-proof net in advance, and reduce the insect population base.
This article was edited and collated by cathay pacific's technical team
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Article Source: Tianbao Agricultural Technology Service Platform (ID: tianbaonj)