Thrips are hidden pests in agricultural production. They are only 1-2 mm long but reproduce rapidly, often causing the curling of young leaves and hardening of fruits, which seriously affects yields. The following is a summary of practical techniques from the aspects of pesticide classification and control points to help you accurately control insects.
Core pesticide classification and application
1. Chemical synthesis: the main force for rapid insect control
(1) Neonicotinoids: Imidacloprid, thiamethoxam, etc. have both systemic and contact effects. 25% thiamethoxam can be used for cowpea thrips control, 15-20 grams per mu spray; Dinotefuran is highly effective against onion thrips, 50% soluble granules are used at 10-20 grams per mu.
(2) Pyrethroids: High-efficiency cyhalothrin has a fast contact effect, and thrips poisoning can be seen within 1 hour, but the effective period is only 3-5 days, which is suitable for emergency insect control.
(3) Diamides: Cyantraniliprole has strong systemic properties. Spray 40-50 ml of 10% suspension emulsion per mu. Pests stop moving within 24 hours. It can also treat aphids and cotton bollworms.
2. Biological agents: The best choice for green control
(1) Spinosad and its derivatives: 12-15 ml of 10% spinosad suspension per mu for controlling cowpea thrips. Ethyl spinosad is particularly effective against watermelon thrips. 40-50 ml of 60 g/L suspension per mu.
(2) Entomogenic fungi: Metarhizium anisopliae and Beauveria bassiana are effective against both adults and nymphs. They are particularly suitable for the control of resistant thrips. However, they need to be used 7-10 days apart from fungicides.
(3) Plant-based agents: Matrine, wolfsbane, etc. kill insects through contact and stomach poisoning. They are toxic to fish and should be avoided from polluting water sources.
3. Other functional agents
(1) Spirotetramat: Long-lasting effect in killing eggs, but effective in 3-5 days. 22.4% suspension 25-30 ml per mu is suitable for preventive use.
(2) Tolfenpyrad: Effective against both eggs and adults. 50% water-dispersible granules 10-20 g per mu spray, effective for 10-15 days.
(3) Diatomaceous earth: Physical adsorption insecticide. 88% wettable powder 1000-1500 g per mu spray, no risk of drug resistance.
Key strategies for scientific control
1. Accurately grasp the timing of control
(1) Development stage: The 1-2 year old nymph stage is the best window period. At this time, the insect body is wingless and gathers on the back of the leaves, which is sensitive to the agent.
(2) Day and night pattern: Thrips are afraid of light. It is best to use the drug in the evening or early morning. When applying the drug, surround the plot from the four sides to the middle to prevent the adult insects from migrating.
2. Resistance and green control scheme
(1) Resistant thrips: Spinosad, tolfenpyrad, etc. are preferred, and blue sticky insect boards are used to lure and kill adult thrips.
(2) Long-term management: Thiamethoxam granules are applied in holes for soil treatment to kill soil-dwelling thrips eggs, and foliar spray is used to achieve both top-down and bottom-up control.
Precautions
1. Organophosphorus pesticides such as carbosulfan are prohibited from being used on vegetables, fruits and melons; pyrethroids are highly toxic to bees and fish, and should be used with caution during flowering and near water sources.
2. Avoid mixing biopesticides with fungicides. When using them, pay attention to temperature and humidity conditions to ensure that the efficacy of the pesticides is achieved.
3. Thrips adults are good at flying, so the pesticides should be a combination of contact and systemic types, and focus on spraying hidden parts such as the back of leaves, heart leaves and flower organs.
