What are the control methods for thrips infestation?
Thrips adults and nymphs rasp and suck the sap of young plant tissues (shoots, leaves, flowers, fruits, etc.). The damaged young leaves and shoots become hard, curled and withered, the plant grows slowly, and the internodes shorten. Young fruits (such as eggplant, cucumber, watermelon, etc.) become hardened after being damaged, and in severe cases cause fruit drop, seriously affecting yield and quality. Let's take a look at the control methods for thrips infestation below!
Damage characteristics of thrips
1. Leaf damage: After young leaves are damaged, the leaves become thinner, gray-white or gray-brown stripes appear on both sides of the leaf midrib, the epidermis turns gray-brown, deformation and curling occur, and the growth vigor is weak. It is easily confused with the damage caused by the broad mite (Polyphagotarsonemus latus).
2. Young fruit damage: The oil glands in the epidermis rupture, gradually lose water and shrink, and the scars expand as the fruit enlarges, showing suberized silvery-white or gray-white scars of different shapes, but a small number also occur on parts such as the fruit waist.
Agricultural control of thrips
1. In early spring, clear weeds and dead branches and fallen leaves from the field, burn them in a centralized manner or bury them deeply, and eliminate overwintering adults and nymphs.
2. Strengthen fertilizer and water management to promote robust plant growth and reduce damage.
3. Taking advantage of the thrips' habit of being attracted to blue, set up blue sticky boards in the field to trap and kill adults. The height of the sticky boards should be level with the crops.
Chemical control of thrips
1. Rice: For rice thrips, thiamethoxam-type products are recommended, including the imported product Rui Sheng 30% thiamethoxam suspension seed coating agent and the domestically tested product Bai Rui 35% thiamethoxam suspension seed coating agent.
2. Vegetables: For thrips on solanaceous fruits, cucurbits, legumes, etc., use 25% thiamethoxam water-dispersible granules at 3000-5000 times dilution for root drenching, to reduce the occurrence of viral diseases and at the same time reduce damage from underground pests. Imported product: Actara; well-known domestic product: Da Gong Niu.
3. Fruit trees: For crops severely damaged by thrips such as mango, 25% thiamethoxam Da Gong Niu can be used for spraying, but the application rate should be increased, such as spraying at 800 times dilution, and it can also be tank-mixed with microemulsion formulations of abamectin.
4. Tobacco: For tobacco, root drenching before transplanting or root spraying at planting can use imidacloprid, thiamethoxam, and clothianidin, with 25% imidacloprid at 1000 times dilution and 25% thiamethoxam Da Gong Niu at 3000-5000 times dilution.
Key points for thrips control
1. Based on the thrips' characteristic of hiding by day and coming out at night, it is recommended to apply the pesticide in the afternoon.
2. Thrips have strong hiding ability, so the pesticide should be systemic or added with an organosilicon adjuvant, and a pesticide with a long residual effect should be chosen as much as possible.
3. If conditions permit, it is recommended to combine pesticide fumigation of the greenhouse with foliar spraying.
4. Thrips should be prevented in advance; do not wait until they have spread out of control before applying pesticide. When planting vegetables during high-temperature periods, if plastic film is not used as mulch, the pesticide should preferably be sprayed simultaneously on the middle and lower parts of the plants and on the ground, because these places are the habitats of thrips nymphs.