Whether it is planting melons, fruits and vegetables, or planting field grain crops, or managing the planting of orchards and fruit trees, the last thing our farmers and friends want to see is the occurrence of diseases and insect pests on their crops, and what they most hope to see is that the crops planted on the cultivated soil can have a good yield and good quality in harvesting. As long as our farmer friends continue to summarize and accumulate correct agricultural planting technology and pest control technology, we can greatly reduce the incidence of diseases and insect pests by strengthening field management and taking comprehensive control measures, and reduce the degree of harm caused by diseases and insect pests to crops.
At present, the whole country will gradually usher in a hot summer, when the temperature is high and the humidity is high, and for all kinds of crops grown in the field, the threat of thrips will be threatened from June to August every year. Thrips is a small pest that makes our farmer friends more headache-sucking, its insect body is small, strong hiding, so it is generally difficult to find when insect pests occur sporadically; at the same time, thrips have a wide range of occurrence, parasitic hazards of crops, plus it has multi-generational reproduction, multiple insect states (thrips have eggs, nymphs, pupae, adult insects four kinds of insect states) generational reproduction superposition, year-round hazards (winter mainly occur in warm and humid greenhouses), strong drug resistance characteristics, This makes it very difficult for our farmer friends to control; in addition, thrips are pests of the stinging mouth, which feed on the branches and leaves of crop strains for a living, so thrips are also the main way for the spread of many diseases such as viral diseases on crops. In the prevention and management of thrips, at present, most of the farmers and friends are annual prevention, year after year, medicine is not less, money is not spent, but it is impossible to prevent every year, the reason is that on the one hand, everyone has not fully understood the insect characteristics and insect pest laws of thrips, on the other hand, everyone has not mastered the best time and the best control method for thrips control.
Before the arrival of the peak of the summer outbreak of thrips, today's agricultural technology small back basket will systematically introduce the insect pest characteristics of thrips to our farmer friends, the reasons why thrips are difficult to control, and the correct comprehensive control methods of thrips, for the reference of our farmers and friends.
<h1 class = "pgc-h-arrow-right" >, the insect infestation regularity of thrips</h1>
1. Common thrips species, distribution and range of harmful crops
We often say that the thrips do not refer to a specific pest, but to a general term for the pests of the order Lentillins. At present, although there are as many as two or three hundred species of thrips that have been found in China, the common thrips with high incidence and heavy harm in crops mainly include the following: (1) onion thrips, which occur more in the northern region; (2) melon thrips, which occur more in south China; (3) rice thrips, which occur in the north and south regions; (4) western thrips, which occur more in the northeast, north China, central China, and east China; in addition, there are ginger thrips that mainly harm ginger crops.
Thrips have a very strong environmental adaptability and omnivorous, can parasitize on many kinds of crops and weeds for reproductive hazards, whether it is melon and vegetable crops, or field food crops, whether it is fruit tree crops or cash crops, or flower seedlings, will often be harmed by thrips. Among them, the onion thrips mainly harm garlic, green onions, leeks, onions, cotton, eggplant, potatoes, cabbage and other crops, melon thrips mainly harm tomatoes, cucumbers, bitter melons, eggplant, watermelon, melons, winter melons, cowpeas, potatoes and other crops, rice thrips mainly harm wheat, corn, rice, sorghum, tobacco, sugarcane, broad beans and beans and other crops, westflower thrips are mainly harmful to teasing crops such as peppers, strawberries, peas, carrots, lettuce and other crops; in addition, apples, pears, peaches, grapes, mangoes, longan, Fruit trees such as lychees and citrus, as well as various types of flower seedlings, are also commonly affected by thrips.
2. Characteristics and living environment of thrips insect pests
From the thrips suitable environment, warm and dry environment is more conducive to the life of thrips, of which the environment suitable for the survival and harm of thrips is 23-28 degrees, air relative humidity 40-70%, when the temperature is higher than 30-35 degrees or the air humidity tends to be saturated, thrips will be difficult to survive, insect infestation will be greatly reduced or not to occur; therefore, in the high temperature, dry air season and the incidence of regional thrips is relatively high, such as poor water retention plots, Thrips are in full bloom from March to May in spring and September to November in autumn.
From the thrips life habits, on the one hand, the thrips are afraid of strong light, like tender and sweet, but also have a strong bluening and diurnal night out of the habit, during the day generally hide the young shoots, young leaves, flowers and leaf backs, petioles, curly leaves and other parts of the crop plant, wait until the sun sets, after the evening comes, the thrips hidden during the day will come out to suck the sap in the tissues of the young parts of the crop for feeding hazards; on the other hand, the thrips are very small, generally not easy to find, and it has wings and legs, both can fly and jump, The harm of spreading in the field is relatively large, and it is easy to escape when spraying and preventing, and it is easy to move back after the effective period of medicine, which can be regarded as a more cunning "pest". At the same time, thrips can parasitize in shallow soil, rock crevices and various crops, weeds, etc. to survive or overwinter in that year, and will multiply in a suitable temperature and humidity, and spread with the help of seedlings, wind, agricultural tools, etc., and then become the source of transmission of thrips on field crops in the following year, it can be said that the accumulation of thrips in the field in that year directly determines the degree of thrips on the field crops in the following year.
From the law of propagation and propagation of thrips, in the case of suitable temperature and humidity environment, thrips in spring, summer, autumn and winter can reproduce hazards all year round, but spring, summer and autumn mainly occur on open crops, and winter mainly occurs on crops in greenhouses; thrips have a very strong reproductive and propagation ability, on the one hand, it can reproduce more than ten generations a year, each generation can lay hundreds of eggs, and each egg only takes about 14 days to develop into adults, and thrips are generational superimposed breeding hazards. If the prevention and control of thrips infestation occurs in the field is not timely, it is easy to cause a large-scale outbreak of thrips. Among them, the larger thrips that are more harmful to crops are nymphs and adults of thrips.
From the high incidence period and easy conditions of thrips, because thrips are most suitable for living in a warm and dry environment with a temperature of 23-28 degrees and a humidity of about 40-70%, and the climate environment of April to June and autumn from September to November is more in line with this characteristic, so the two periods of spring and autumn are the high incidence of thrips, and the thrips infestation generally begins after the weather warms up in mid-March every year, and lasts until the weather cools in mid-to-late November in autumn. After that, the adult thrips began to enter the overwintering period. In addition, from the type of thrips, the high incidence period of onion thrips is from mid-May to mid-to-late June, mainly to harm all kinds of melon fruits and vegetable crops, the high incidence period of melon thrips is from mid-to-late May to mid-July, late August to mid-to-late October, mainly to harm onions, ginger, garlic, leeks and other vegetable crops, the high incidence period of corn thrips is mid-to-late May to mid-july every year, mainly to harm spring corn, summer corn, wheat, peanuts and other field crops. The high incidence of carob thrips is from May to June and from August to October. Because there are so many types of thrips, I will not elaborate on them here. However, it should be noted that thrips are frequent insect pests in warm and dry environments, in years with higher winter temperatures, faster spring warmer years, warm and arid climates, sandy plots with poor water retention, plots with excessive use of nitrogen fertilizer and insufficient use of phosphorus and potassium fertilizers, plots with excessive crop plant growth, plots with poor ventilation and light transmission in the field, plots with overgrown fields, plots with incomplete cleaning in winter and spring fields, plots with extensive field management, and plots with continuous stubble planting and long-term single medication. Thrips have a large field accumulation and early and heavy insect infestation, but in plots with heavy soil viscosity or continuous rainy weather and large soil moisture, thrips will relatively reduce the occurrence of insect pests due to poor living environment and difficulty for adults to enter the soil to overwinter.
From the perspective of the harmful symptoms of thrips infestation, because the thrips mainly feed on the sap in the tissues of the more tender parts of the crop plants, the young shoots, heart leaves, tender leaves, flowers, young fruits, etc. on the crop plants are more seriously affected, and the plants with more serious thrips infestation will have growth point atrophy, heart leaves will shrink /curl, the leaves are hard, rough or gray and white spots, flower organs are dysplastic, deformed and withered, flowers are sterile or prematurely withered, plant growth is slow, flowers are not fruit, flowers fall early, filling discomfort, Problems such as empty grains, ossification and deformity of young fruits, and increased markings on the fruit surface, at the same time, thrips will also carry bacteria and poisoning, causing field crops to induce a variety of viral diseases, gray mold and other diseases.
<h1 class="pgc-h-arrow-right" > second, why is thrips difficult to control and eradicate? </h1>
The reason why thrips are difficult to prevent and treat is related to its own insect infestation characteristics on the one hand, and on the other hand, it is related to the extensive field management and improper control methods of our farmer friends.
1, thrips it is small, good at hiding and has the characteristics of day and night, it is generally difficult to find when sporadic occurrences in the field, and when our farmer friends find out, the amount of insects in the field has been very "considerable", and it is naturally more difficult to control.
2, thrips it can be reproduced at any time throughout the year, spread, harm, a year can breed more than ten to twenty generations of range, both female single reproduction, can also be male and female reproduction, an adult worm can reproduce dozens to two or three hundred eggs each time, and thrips from eggs to the development of adult worms only need more than ten days of time, if the early field sporadic occurrence of prevention and control is unfavorable, the accumulation of thrips in the field in the later period will show geometric multiples of growth, so the difficulty of prevention and control is relatively large.
3, thrips it hides in the hidden place of crops during the day, and our farmer friends are generally accustomed to spraying during the day, on the one hand, it is difficult to make the liquid of the medicine difficult to contact the body of the thrips during the daytime, on the other hand, the thrips have wings to fly, legs to jump, when spraying can "escape" out of the field, wait until after the spray and then return to continue the harm, on the one hand, our farmer friends often have "effective drugs can be used for a long time" when using drugs, "the medicine map is simple and rough spraying", In addition, our farmers do not spray medicine according to the characteristics of thrips, especially in the early stage or early stage of drug control. In this way, even if the field crops are often sprayed or more drugs are sprayed, the thrips "cannot be killed, cannot be removed, or the insect pests recur after the spray".
4, our farmer friends in the field crop planting management, there is often an excessive partial application of nitrogen fertilizer, in the pest control and management of diseases and insect pests also exist only spray crop plants or the bad habit of the ground, excessive use of nitrogen fertilizer solution leads to crop seedlings growing, plant branches and vines and leaves are closed and airtight, spraying only crop plants and the ground will lead to thrips in the field when spraying to escape the weeds in the field "hiding from the wind", both easy to create a favorable environment for thrips to hide and reproduce, but also easy to spray incompletely, but also easy to lead to thrips drug recurrence.
In addition, the agricultural technology basket has been mentioned to everyone above: thrips can parasitize in the soil gaps, gravel weeds and straw residues in the field or overwinter, our farmer friends before sowing or after the harvest, if you do not turn the planting ground deep in advance to dry, or do not thoroughly clean the field, it will lead to the field thrips spread more and more sources of insects, resulting in the phenomenon of thrips infestation increasing year by year.
<h1 class="pgc-h-arrow-right" >3. How to correctly and scientifically control thrips? </h1>
Prevention and control of thrips, can not rely only on insect pests after the occurrence of medicine is unable to prevent, can not be extinguished, in order to completely and effectively control thrips, we farmers and friends should be from the crop sowing to the whole season after crop harvesting for prevention and treatment, and the comprehensive use of a variety of prevention and control measures for "multi-pronged" governance, if a link problem is easy to lead to the failure of thrips prevention and management. So, many peasant friends have to ask: How should we prevent it?
1. Thoroughly clean up the field before sowing and after harvesting
In the 15-20 days before crop sowing, the soil should be turned into a deep drying mound of about 20-30 cm in advance, and with the help of deep ploughing and drying of the soil, some of the insect sources hidden in the soil can be turned to the ground to kill by ultraviolet rays in the sun.
Whether it is open-field planting or greenhouse planting, whether it is before crop sowing or after crop harvesting, the remaining straw weeds, dead branches and leaves in the field should be comprehensively and thoroughly cleaned up, and then all of them should be moved out of the field for centralized incineration or deep burial, which can effectively reduce the number of insect sources accumulated by thrips in the field.
In addition, orchards should use the winter and spring fruit tree dormancy period for thorough clearance, and greenhouses can use the summer break period to carry out high temperature and wet alternating dry and wet shed treatment.
2, reasonable stubble rotation, scientific planting, to avoid long-term stubble and planting density is too large
On the one hand, for all crops that are prone to thrips infestation should not be replanted year after year, otherwise it is easy to lead to the accumulation of thrips in the field year by year, it is recommended that crops that are prone to thrips infestation and crops that are not easily harmed by thrips be stubble for 2-3 years, if possible, it is best to carry out 2-3 years of stubble with paddy crops such as rice, which can effectively kill the cumulative source of thrips in the field.
On the other hand, for crops prone to thrips infestation or plots with heavy thrips infestation, it is recommended to reasonably control the density of sowing to prevent excessive density in the field and airtight plants from further aggravating the pest situation.
On the other hand, for fields with heavy insect infestation, the whole field can be flooded with water in advance according to the moisture situation before sowing, and the amount of irrigation should be sufficient and the soil of the field should be filled, which can effectively kill the thrips eggs and adult insects remaining in the soil.
In addition, for watermelon, eggplant, pepper, cucumber and other crops that need to be transplanted and colonized, it is best to use 1000 times 25% imidacloprid or 4000 times 25 times thiamethoxam to dip the roots before colonization or irrigate after colonization, so that the seedlings can be planted into the soil to isolate the thrips infestation, thereby reducing the harm of thrips to seedlings.
3. Strengthen water and fertilizer management and cultivate robust seedlings with strong disease and insect resistance
Reasonable water and fertilizer supply is conducive to cultivating robust seedling growth, and robust seedling growth can enhance the physiological resistance, disease resistance and insect resistance of crop plants themselves. Generally speaking, in the base fertilizer of the crop, it is recommended to take the decomposing organic fertilizer as the mainstay, supplemented by phosphorus and potassium fertilizer, and use nitrogen fertilizer in an appropriate amount (the amount of nitrogen fertilizer per mu should not exceed 10 kg), if it is topdressing, that is, the appropriate amount of phosphorus and potassium fertilizer should be increased, nitrogen fertilizer should be strictly controlled, and at the same time, it is necessary to pay attention to the foliar spraying of potassium dihydrogen phosphate, borax solution, zinc sulfate, chelated calcium, magnesium sulfate, rare earth solution and amino acid foliar fertilizer, in order to ensure that the nutrient supply during the growth period of the crop is sufficient and comprehensive, and the plant growth is vigorous and robust. In terms of watering management, crops should be as little watering as possible on the basis of better sowing water, colonization water, and slow seedling watering before flowering and fruiting, and then gradually increase the amount of watering after the first spike of flowers and fruits sits on the first ear to promote the filling or expansion of the fruit spike, but when watering, according to the weather precipitation, the degree of soil dryness and wetness, and the growth trend of seedlings, watering in the morning and evening, keep the soil dry and wet, try to take sub-membrane watering, sprinkler irrigation, drip irrigation and other watering methods, but pay attention to try to avoid flood irrigation, soil for a long time or prevent long-term soil drought and lack of water , otherwise it is easy to affect the normal growth of crops. In addition, it is recommended to keep the soil moist during crop growth to inhibit the multiplication and spread of thrips infestations that prefer dry environments.
4. Greenhouse crops should pay attention to regulating the temperature and humidity environment in the greenhouse
For greenhouses, due to the relatively closed environment, if the temperature in the greenhouse is too high, it is easy to induce serious thrips infestation. To this end, in the management of the shed, before the arrival of the high incidence of thrips, if the temperature in the shed is too high, it should be timely vented to cool down, or through the plant spraying water or morning and evening field watering to keep the soil moist, in order to inhibit the breeding and spread of thrips.
5. Physical control and biological control methods of thrips
On the one hand, in view of the characteristics of thrips tending to be tender and blue, after the occurrence of thrips infestation in the field crops, it is possible to trap the adult thrips by hanging a blue slime plate with a size of 25 cm * 30 cm at the top of the field crop or about 10 cm above the top of the plant. The blue sticky oil board can be used to brush blue paint on both sides of the wooden board, brush the sticky shellac or fertilizer oil on both sides after drying, or directly purchase the finished blue sticky oil board.
On the one hand, in view of the tender and sweet characteristics of thrips, after the occurrence of thrips infestation in field crops, thrips can be booby-trapped by placing a sweet and sour solution between the rows of field crops. The sweet and sour solution can be prepared according to the proportion of 5-8% brown sugar + 1% vinegar aqueous solution + a small amount of insecticidal drugs (such as dimethods, etc.).
On the other hand, in view of the characteristics of thrips often flying around during the high incidence of thrips, we can prevent external thrips from flying into the field crops by means of temporary insect nets above the field or at the vents of the shed during the high incidence of thrips. It should be noted that because the thrips are relatively small, we should choose a dense 40-50 order insect net in the use of insect nets.
On the other hand, for protected areas or green planting plots, spraying may reduce the quality of crops, for this reason, we can find that after the occurrence of thrips infestation in the field, grass age, plants, red-eyed bees, flower bugs, etc. are released in 2-3 times to catch natural enemies such as thrips for food.
6. Timing and method of drug prevention and treatment of thrips
To prevent and control thrips infestations, we should seize the best time for prevention and control to carry out early prevention, smart treatment, and comprehensive use of multiple measures. The specific prevention and control methods are as follows:
On the one hand, before the arrival of the high incidence of thrips infestation in spring, summer and autumn every year, or during the new and slightly young leaves and flowering and fruit setting periods of crops, the best control time for thrips to spawn, hatch and unearth should be seized, and the eggs and pupae of thrips should be killed by taking drug spraying or deep ploughing of the land.
On the one hand, during the growth period of crops, the field insect situation inspection and detection should be strengthened, when there are 3-5 thrips on each crop, it should be sprayed with drugs in time for prevention and control, the best time to spray medicine is to choose thrips to concentrate on feeding, strong activity in the evening or early morning, can not choose the thrips in hiding during the day when the strong light of the day to spray.
On the one hand, when spraying, it should focus on spraying the leaf back, petiole, tender slight, heart leaf, young fruit and other young parts of the crop that thrips like to hide, and to spray the surface soil gaps, gravel, weeds and shed pilasters around the field, etc. When spraying, choose a sprinkler with better atomization, spray the spray from the outside to the inside to spray the spraying liquid uniformly, if the insecticide effect is not good after spraying, you can spray it back once in 2-3 days, so as to kill the thrips that have slipped through the net and escaped during the spraying and flew back after the spraying. Under normal circumstances, the prevention and treatment of thrips generally requires 2-3 consecutive sprays of the actual effect of prevention and control, and 1 spray every 5-7 days.
On the one hand, in order to improve the effect of drug prevention and control, it is recommended to add some sugar liquid, neutral laundry detergent, silicone and other auxiliary substances that have the effect of attracting thrips or improving the effect of extending penetration of the liquid when spraying, so as to improve the effect of drug control of thrips insect pests.
On the one hand, in the choice of drugs, the commonly used drugs for the prevention and control of thrips are imidacloprid, acetamiprid, thiamethoxam, thiamethoxam, thiamethoxine, prayfenone, cypermethrin, avermectin, chlorantranilifran, bifenum, mewi salt, zolazolinamide, chlorofluoride • thiamethoxam, cypermethrin, pyripronide • carbonitrile, ethyl polyfungalin, mevinia asterone, matrine, etc., should avoid long-term single medication, it is recommended to choose 2-3 kinds of targeted control drugs for alternating spraying, In particular, in the thrips pest plots that have become resistant to drugs, attention should be paid to avoiding the use of organophosphorus, permethrin and other drugs that are easy to reduce the control effect of drugs, and at the same time, the insecticide effect should be improved by adding auxiliary agents to the liquid or using drugs with strong systemic permeability.
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