There are many measures to control vegetable thrips by scientific methods, but the condition of scientific and reasonable measures is to master the main causes of vegetable thrips, and to know and find pests timely and accurately on the basis of mastering the typical symptoms of harm.
1. Reasons for improper treatment of cultivation environment: thrips fall into soil layer or green plant residues after pupation, and stubble cleaning or disinfestation in the cultivation area is not complete before planting or transplanting, and pupae will ovulate when encountering suitable environmental conditions. If the last crop has been damaged by thrips, the risk of insect pests will further increase under cultivation conditions.
Outward migration: thrips not only occur frequently on vegetables, but also on crops such as rice. At the same time, it is very easy to migrate between different crops, causing cross-harm. If there are crops with thrips in the surrounding land of Leguminosae, Cucurbitaceae and Solanaceae during the growing period, thrips can move in by their own flying ability.
Improper prevention and control measures: in a warm and arid environment, one's own reproductive ability will be improved and there will be overlap between generations. When the standard is appropriate, it takes only two weeks for thrips to go from egg to nymph, and from the current situation of pest control, thrips have developed extensive resistance to commonly used drugs. If the control time is not well grasped, or the medicine is improper, thrips will easily break out. At the same time, due to its small size, in the early stage of pest occurrence, the best control stage is often missed because of careless observation.
Second, the symptom of thrips is sucking mouthparts, which mainly harms the tender position of plants. After eating, the young leaves of beans can be deformed, the tips shrink and stop growing, and the nodes become shorter or scattered. Flowers of vegetables such as beans, pumpkins, eggplants and peppers are important parts that thrips like to hide and eat. After damage, it is easy to cause flower drop, pod drop and fruit drop. The damaged young pods develop slowly, the deformity rate increases, the epidermis is not smooth, and rust spots are produced, which seriously affects commercialization.
Third, the prevention and control measures of vegetable thrips thrips have the law of life in the daytime and at night. When the weather is good, they will hide in flowers or on the back of leaves, and rainy days and morning and evening are active periods. The main measures to control thrips in production include:
(1) After obtaining the last crop harmed by thrips, the plant residues should be thoroughly removed, burned or buried centrally, and then the survival number of larvae and pupae should be reduced by spraying chemicals or infiltration irrigation, which can play a multiplier role in the subsequent occurrence and control of thrips in vegetables.
② Hanging blue armyworm or hanging trap lamp armyworm are mainly divided into yellow spots and rebound, among which thrips have a strong preference for blue. 1 mu vegetable field has 30-35 backboards, and the relative height is similar to that of bud eyes. This method has good control effect in greenhouse vegetable cultivation. Under the premise of open field, due to the influence of rain or continuous high temperature and sun exposure, the control effect is often reduced.
③ Plastic film mulching cultivation According to the characteristics that thrips pupae will fall into the soil layer and then transfer to the ground plants after being covered, plastic film mulching can effectively block the safe passage of insect pupae being buried. Insect pupae falling on agricultural plastic film often can't survive because of the high temperature of the endothermic reaction environment of agricultural plastic film and no dark and humid substitute, thus reasonably reducing the probability of insect pests.
(4) Under the production conditions of greenhouse with good smoke control and sealing standards, 25% mites, isoproterenol or 15% smoke protectant can be selected for fumigation, which is time-saving, labor-saving, efficient and thorough. Smoke agent should be evenly placed in the shed. The sulfur content in smoke agent, too much or often used, will harm the function of leaves, so it is necessary to strictly refer to the dosage.
⑤ The common chemicals sprayed are pyridaben, chlorfenapyr, thiamethoxam, flufenoxuron, rice blast amide and ethyl spinosad. The key period of control is flowering, and the most suitable time for pesticide application is before 9 am, when the petals are open and thrips are active. In the afternoon, many vegetable petals, including beans and okra, closed, resulting in pesticide blind spots, which reduced the control effect.
It is best to mix pesticides (thiamethoxam, etc.). ) and ovicide (fluorouridine, etc. ). At the same time, 25g of white sugar can be added to every 15L water by taking advantage of the sweet taste of thrips. In addition, adding silicone additives can enhance the curative effect of drugs.
Finally, it should be reminded that the control of thrips must be carried out in advance, whether it is hanging armyworms, fumigation or spraying chemicals, so as to get twice the result with half the effort, especially in the early flowering period of vegetables. In daily management, we should pay attention to check whether thrips are hidden in the back of leaves and flower organs, and take comprehensive measures to deal with them, so as to truly achieve "prevention first, comprehensive prevention."