Leek late-eyed mushroom mosquito (leek maggot) green prevention and control technology
Leek Chi-eye mushroom mosquito (Bradysia odoriphaga?? Yang?et? Zhang) belongs to the genus Dipterae, also known as leek maggots, leek maggots, root maggots and so on. It is an omnivorous pest, which can harm more than 30 kinds of vegetables and a variety of edible mushrooms in 7 families, mainly leeks, onions, garlic, leeks, chives, especially leeks. The insect is a unique pest species in China, which occurs almost all over the country and has become the main factor restricting the development of the leek industry.
Green prevention and control is through the selection and assembly of control technologies, priority is given to the use of ecological regulation, biological control and physical control and other environmentally friendly technical measures to control crop diseases and insect pests, the scientific use of chemical pesticides, to minimize the use of chemical pesticides, to ensure the safety of crop production, agricultural ecological security and agricultural product quality and safety. Taking important target diseases and insect pests as the main line, assembling green prevention and control technology or products is an important model for the integration of green prevention and control technology, which is conducive to accelerating the promotion of plant protection technology. In view of the harmful characteristics of chick-eyed mushroom mosquitoes, the integration of green prevention and control technology is proposed, in order to provide theoretical reference for the safe production of leeks and contribute to the healthy development of the leek industry.
1 Occurrence status quo
Chickoptera chictosis has no diapause characteristics, as long as the temperature and humidity are suitable, it can reproduce all year round. In the open leek field on the outskirts of Beijing, 4 generations can occur in 1a (year), and the generation overlaps significantly, and the overwintering larvae begin to be infested in late March, and the 4th generation larvae gradually enter the soil in late October to overwinter. Spring and autumn are the main pest seasons, from April to June and from September to October, respectively, of which mid-May and early September are the peak periods for larval pests, and the field pests are significantly reduced from July to August. The production of arch sheds is common, the spring shed is harmful in advance, and the larvae are aggravated after the autumn shed is delayed. Greenhouse leek fields can occur annually, and will gradually worsen after the winter shed, and the peak of larval pests will occur in mid-to-late March, and the characteristics of occurrence after removing the shed film are basically the same as those in the open ground. The occurrence of new leek fields is generally mild, with more than 85% of leek maggots in leek fields above 2a (year), and the rate of insect bushes in severe fields reaching more than 95%. The loss caused by leek maggots is generally large, and in general, it can lead to a reduction in production of 20% to 30%, and the production reduction of more than 50% in the heavy cases, and poor prevention and control can lead to the destruction of seeds and harvests.
2 Harmful characteristics
The leek late-eyed mushroom mosquitoes mainly overwinter as larvae at the base of the leek leaf sheath, in the bulb and in the soil around the leek root, and mostly spawn in hidden places such as the soil crevices around the rhizome of the leek plant, under the soil block and the leaf sheath gap (color plate 1). The hatching larvae crawl downwards, nibbling on new shoots and young stems of leeks, or gathering to feed on the lower part of the leaf sheath and the upper part of the bulb (color plate 2), puncturing the epidermis and decaying the internal tissues of the moth, and decaying as the feeding wound continues to decay (colored plate 3). New shoots and young stems are affected, with the lightest leaf deformities (color plate 4) and weak growth, and the heavy ones hurting the growth point, resulting in the inability to produce a tree (color plate 5). Leaf sheath damage, the outer leaves first show symptoms, the initial leaf tip or unilateral strip yellowing wilt (color plate 6), then the whole plant yellowing, leaf wilting, and finally leek yellow wilt lodging (color plate 7). Bulb damage, in addition to causing the plant to wilt and lodging, when severe, the entire bulb rots and the leek bush completely dies. Fields generally occur in dots, and heavily affected fields show a lack of seedlings and ridges (color plate 8).
3 Main prevention and control difficulties
The author's investigation found that many vegetable farmers lack the awareness of preventing the occurrence of leeks, have a vague understanding of the occurrence of leeks and the characteristics of harm, and are not clear how to avoid or reduce the occurrence of leeks. In addition, leek maggots are underground pests, the initial damage is difficult to detect, it is not easy to find in time, often after the discovery of the insects has been large, the field damage is serious, so that have to use chemical pesticides. At present, the application method of registering agents for this insect on leeks is mainly to irrigate roots and mix soil, and the dosage is generally large, and the safety interval is generally long. The harmful characteristics of leek maggots determine that it is difficult to be completely controlled, and farmers are very prone to over-medicating, and cannot ensure sufficient pesticide safety intervals, resulting in excessive pesticide residues in leek products. Overdose can also lead to resistance to pests, resulting in reduced control effects and even failure of control, forming a vicious circle. What's more, they will abuse highly toxic and illegal pesticides to prevent and control leek maggots. Leek product quality and safety incidents caused by improper use of chemical pesticides occur from time to time.
4 Green prevention and control technology integration
The green prevention and control of chickoptera must adhere to the plant protection policy of "prevention first, comprehensive control", and control adults and larvae at the same time, and do a good job in population control. Among them, the prevention work should be mainly based on agricultural prevention and control, supplemented by the release of natural enemies; the prevention and control work should be mainly based on chemical agents, and ecological regulation and control technology should be paid attention to.
4.1 Agricultural control
4.1.1 Clean the countryside Avoid the previous stubble as a lily crop, and implement rotation of more than 3a (years). Leek seedlings and colonization plots should be selected with loam soil with convenient drainage and irrigation and fertile texture, and the distance from the planting plots of lily crops such as onions, leeks and garlic and edible mushroom planting sheds is more than 100m. Leek residues in the field can attract adult leek late-eyed mushroom mosquitoes, and leek residues and uncorried organic fertilizer should be avoided in and around the leek field. Deep ploughing of the soil before sowing or before colonization, cleaning up all kinds of debris, and drying the soil for about 7 days (days) can make the various insect-like leeks in the soil die and reduce the amount of insect sources.
4.1.2 Planting mode The damage of leek maggots to leeks is a gradual process, and when the amount of insects is low, due to the tillering characteristics of leeks themselves, there will be a compensation effect. Therefore, varieties with strong tillering ability, compact plant type and good uprightness should be selected, and reasonable dense planting should be used to compensate the yield and enhance field ventilation after the leek maggots are mildly damaged. When transplanting, try not to plant a single plant, and it is advisable to plant a small cluster and a small ridge cluster.
4.1.3 Fertilizer water management With the increase of fertilizer application of leek maggots, considering the long growth period of leeks and the large demand for nutrients, it is necessary to apply plantar fertilizer before colonization, but not too much. Fertilization can be applied according to soil fertility, and fertilization can be applied with a testable soil formula with conditions. During the summer rooting period, water control and fertilizer control, timely drainage. Larvae prefer to eat scavengers, and spreading substrates such as straw and coconut bran between leek rows can promote the aggravation of leek maggots (color plate 9), which should be avoided. Controlling surface humidity is conducive to reducing the occurrence of leek maggots. The use of drip irrigation in the production of leeks in facilities is conducive to reducing the insect population density of leek maggots.
4.1.4 Harvest management Leek fields with a large number of harvests and a high frequency are easily invaded by leek late-eyed mushroom mosquitoes, and leek maggots are prone to recurrence. From the perspective of preventing and controlling leek maggots, combined with the need for rooting of leeks, the planting and harvesting of leeks need to strengthen planning, and the total number of harvests throughout the year should not be too much, and it is advisable to harvest 2 to 3 times continuously. After harvesting, the residue of the furrow surface can be cleaned in time, and the grass and wood ash can be sprinkled on the surface, which can play a role in reducing the harm of leek maggots.
4.2 Ecological regulation
4.2.1 Cutting leeks and drying roots The planting of leeks in open-ground bushes with more than two years old can be used to pick up the soil and dry the roots before the soil begins to thaw and the leek germinates in the spring, which can significantly reduce the harm of the leek late-eyed mushroom mosquito. Select the weather is good, peel off the topsoil around the leek bush, expose the upper end of the bulb, and remove the topsoil between the leek plants, dry it for 3 to 5 days (day) after closing the leek bush and cultivating the soil. In winter, the production field of the facility can be dried before the shed is dried, and it is advisable to dry it for about 7d (days).
4.2.2 After the harvest of leeks, lay a transparent and insulated non-drip film or a low arch on the ground, and use the good weather to directly sunlight to make the soil temperature exceed 40 ° C and last for more than 3h (hours), which can effectively kill the leeks in the soil. This technology also has a very ideal anti-effect for pests such as thrips, aphids, onion oligoflora and yellow hairy beetles. Considering the light requirements and the needs of leek rooting, it is more suitable to use this technology in leek fields produced in the high temperature season.
4.2.3 High temperature stuffy greenhouse During the summer rooting period of leeks in the greenhouse, the shed film is not removed, the air outlets are properly opened, and the watering is controlled, so that the field is maintained in a high temperature and drought state, which can significantly reduce the number of adult and larvae of leek late-eyed mushroom mosquitoes.
4.2.4 Low temperature insecticidal Leeks produced in winter and spring protected areas can use the outdoor low temperature in autumn and winter to reduce the amount of insects in the early stage of production. The main method is: remove the shed film or completely open all the air outlets, you can also do a wind barrier on the south side, so that the upper part of the leek ground is fully dried up, and timely clean up the dry yellow residue between the furrows; and then determine the temperature time of the buckle shed according to the expected market time. Open leeks (to be sown in the following year) should be watered during the night freeze in the field, and in the Beijing area, it is generally carried out around the end of November. After thawing in the spring of the following year, spring irrigation depending on the moisture situation can also kill some of the overwintering larvae.
4.3 Physical control
4.3.1 Set up insect nets To set up insect nets at the vents and entrances and exits of leek sheds can significantly reduce the occurrence of leek late-eyed mushroom mosquitoes. The size of the insect-proof net set should completely cover the air outlet and entrance. Comprehensively considering the light transmittance, ventilation and ventilation and the need to block the adult insects of the chick-eyed mushroom mosquito, it is advisable to use 40 to 50 insect nets, and dark insect nets can be used for summer cultivation, and colorless insect nets can be used for cultivation in other seasons. In the process of using the insect net, it should be avoided to pull hard to prevent the pore size from being deformed or damaged, and the loopholes should be repaired in time after damage.
4.3.2 Ozone disinfection Ozone is a strong oxidant, which has a certain killing effect on the adult insects of leek late-eyed mushroom mosquitoes, and has a good effect of preventing gray mold, which should be used in the leek field of the protected area. 1 to 2 days (days) after the leek harvest, remove the furrow residue, seal the shed room, and use BT2010-I. self-controlled ozone disinfection room temperature smoke applicator to release ozone disinfection for 4 to 6h (hours). The ideal operating time is 7:00 to 11:00 and 15:00 to 20:00 in late autumn to early spring. In order to ensure the killing effect of ozone, it should be ensured that the shed is closed and the relative humidity of the air is above 70%.
4.4 Physicochemical inducement control
4.4.1 Color plate booby trap Adult leek late-eyed mushroom mosquitoes have a certain tendency to color, black armyworm plate insect attraction effect is better, followed by yellow armyworm plate (color plate 10). 3 to 5 yellow armyworm plates are placed every 667m2 leek field in open field production, which can monitor the occurrence of adult insects in order to carry out chemical control in time. Under protected area conditions, placing 25 to 30 insect trap plates every 667m2 can play a certain role in killing adult insects. Adult leek late-eyed mushrooms generally have a small range of activity and like to crawl on the ground, so the insect trap plate should not be placed too high, and the lower edge of the color plate can be 5 to 10 cm above the top of the plant. During the use of the process of pay attention to the regular replacement of the armyworm board, easy to grasp the dynamics of adult insect occurrence in time. Protected areas should be used in conjunction with insect nets.
4.4.2 Light booby-trapping Adult leek late-eyed mushroom mosquitoes have a tendency towards light. You can choose to use the edible mushroom insecticidal lamp to kill mushrooms and mosquitoes, and the density of the distribution is selected according to the light power. Open-field production should be used in conjunction with field monitoring, starting when there are a small number of adult worms on the sticky worm board and turning on the lights in the evening to early morning.
4.4.3 Odor booby-trapping Adult leek late-eyed mushroom mosquitoes have a tendency to odor. Sugar, vinegar, wine, and water are mixed into a sweet and sour solution in a volume ratio of 3:3:1:10, and then chemical pesticides such as 90% of the original drug of dimethodium or 10% of the suspension of thiamethoxamine are added according to the dosage of 2%, and odor attractants such as allicin can also be added to the sweet and sour liquid to trap adult insects (color plate 11). Care should be taken to combine insect nets for use in protected areas.
4.5 Biological control
4.5.1 Protection of natural enemies in the field In production, attention should be paid to avoiding or reducing the use of broad-spectrum insecticides, and the protection and utilization of natural enemies in nature is conducive to controlling the population of The mosquitoes with chicks. The contiguous area of leek fields should not be too large, and the alternating existence with other plots is conducive to maintaining the biodiversity of the field and avoiding the soaring population.
4.5.2 Release of natural enemies After insect pathogen nematodes are applied to the field, they can actively search for leek maggots, enter the leek maggots through the anus, stomata, etc., and then release symbiotic bacteria, causing leeks to die of sepsis (color plate 12). The advantage of this technology is that it is highly effective, and pathogenic nematodes can actively track pests and continuously control pests. Select a pathogenic nematode strain with good parasitic effect on leek maggots, and release it during the larval infestation period, and pay attention to the temperature and humidity of the ground to be suitable for the large number of pathogenic nematodes. Leek fields in open fields, arches, greenhouses and greenhouses can be used, and insect pathogenic nematodes can also be used in combination with currently registered chemical pesticides.
4.5.3 Biopesticides The only biopesticides currently registered for the control of leek maggots are spore-containing 15 billion ·g-1 coccidioides albicans granules. The results of field experiments showed that the microbial source pesticide avermectin (Xing Jian'an et al., 2007; Wang Ping et al., 2011), Suyunjin bacillus (Cheng Xuemei et al., 1998; Zhang Qiang, et al.; et al., 2002) and fluorescent Pseudomonas (Wu Yanbing et al., 2003), plant-derived insecticides natural pyrethroids (Wang Ping et al., 2011), quinoa and ricinoleic nicotine (Zang Juncai et al., 2000), matrine (Zheng Fangqiang et al., 2002), neem and hypertonic nicotine (Chen Et al., 2005) have all had good control effects, but no registered products have been seen.
4.6 Scientific drug use should strengthen the scientific use of pesticides from three aspects: legal, compliant and reasonable, which is a fundamental measure to avoid or alleviate the quality and safety of leek products.
4.6.1 Selection of registered agents should be adapted to local conditions, adhere to the purchase of legal pesticide products registered for the prevention and control of "leek late-eyed mushroom mosquito" or "leek maggot" from formal channels, avoid the use of non-registered pesticides, and resolutely eliminate the use of highly toxic and prohibited pesticides to control leeks. At present, there are only 1 preparation registered for the control of adult leek late-eye mushroom mosquitoes, which is 4.5% high-efficiency cypermethrin emulsion; there are 18 registered preparations for the control of leek late-eye mushroom larvae, namely imidacloprid wettable powder (content including 10%, 20%, 25%, 50% and 70%), 2% imidacloprid granules, 5% imidacloprid granules, 20% imidacloprids caprylyl thiophos emulsion, 35% octylthiophosphorus suspension, 21% thiamethoxazine suspension agent, 10% thiamethoxam suspension agent, 2% Chlorofluorothiamethiamin Granules, 20% Fly Exterminator Thiamethoxamine Suspension, 28% Insect Mites Thiamethoxamine Suspension, 30% Fluorospyrene Thiamethoxamine Suspension, 50 g · L-1 fluoropyridine emulsion and 10% fluorolingurea suspension. When selecting a drug, it is necessary to consider the problem of drug resistance and pay attention to the rotation of the agent.
4.6.2 Use drugs according to pesticide labels Read pesticide labels carefully and accurately measure the dosage. The dosage and concentration of pesticides should be accurate, and qualified vegetable farmers can use precision medicine measuring tools to accurately dispense drugs, and do not arbitrarily increase or decrease the dosage and concentration. Strictly implement the number of single-season use and pesticide safety intervals, fully consider the relationship between pharmaceutical control and leek harvesting time, if the leeks are about to meet the harvesting standards, they can be harvested appropriately in advance or after harvesting.
4.6.3 Rational use of chemical pesticides (1) Transplanting seedling treatment. Fine seedlings before transplanting leeks colonization, remove weak seedlings, diseased seedlings and leek seedlings with insects, and then use 10% imidacloprid wettable powder 800 to 1000 times liquid or 70% octathion emulsion 500 to 600 times liquid dipped in the root for 1 minute (min), which can reduce the harm of leek late-eyed mushroom mosquitoes in the production period. (2) Field medication. It is necessary to achieve early control, and pay equal attention to adult control and larval control. Adult control should be based on field monitoring, as soon as possible during the peak of adult occurrence, that is, when the number of induced insects increases significantly. Spray before or after 9:00 or after 16:00, and apply the drug forward, paying attention to the solution to cover the leeks, soil surfaces and shed concealments, preferably covering the entire aisle, shelf and shed indoor surface.
Chemical agents to control larvae should avoid the growth period of leeks, and advocate winter production and summer application, and spring production before winter application. The best period for the use of medicine during the growth period is the early stage of larval pest, that is, the field sporadic occurrence of leek leaf tips yellowing and soft gradual lodging, digging roots can see a small number of larvae, if this time from the harvest time can fully ensure the pesticide safety interval, should be immediately applied to control. Combined with winter irrigation, spring irrigation and leek root application, the effect is better. When irrigating roots and spreading pesticides, do not increase the amount of use to improve the prevention effect, and take measures according to local conditions to improve the utilization rate of pesticides. Try to apply the drug in small areas as much as possible, if there is no furrow, isolate it into small areas, and if the furrow is long, apply the drug in appropriate sections. When irrigating the roots, it is advisable to first water and then apply the drug, you can use the sprayer to spray the ground evenly or one by one, piece by piece, which helps to improve the utilization rate of pesticides, and when using the drug, the agent should be diluted into a certain amount of mother liquor as appropriate, and the mother liquor should be no less than 15L per 667m2 leek field; before application, the agent can be mixed with fine sand or fine soil, and the 667m 2 leek field is not less than 30kg of poisonous soil.