Hazardous features: Rice water weevil is a kind of pest that seriously damages rice. Adult food leaves, larval food roots. The larvae are the main hazards. (1) Adults: Adults tend to eat leaf flesh in the direction of leaf veins in the leaf margins or in the middle of the leaves, leaving the epidermis forming long strips of varying lengths, usually no more than 3 cm in length. (2) Larva: The larvae feed on the roots and roots of rice, and the 1st to 3rd instar larvae feed on the roots. After 4th instar, they climb out of the rice root and directly bite the roots. The larvae are densely rooted, the roots are fed, the plants dump when the wind blows, and they are even pulled up and float on the water. Due to the damage caused by the root system of rice, the growth of rice plants is hindered, becomes short, the tillering rate is reduced, the planting rate and the number of grains per panicle are significantly reduced, and the heading date and ripening period are significantly delayed, eventually leading to severe reduction in yield, and the general land reduction by 10 ~ 20%, serious land mass production up to 50 ~ 70%. Control methods: 1. Agricultural control 1. Rational fertilization. In fertilized paddy fields, the larvae have a large amount and grow in a straight line. Therefore, reasonable combinations of nitrogen, phosphorus, and potassium, and scientific fertilization can reduce the population density. 2. Drain irrigation timely. Drainage occurs during the damage period of the last instar larvae to make the soil dry to control the damage of rice water. After early drainage, there is a lack of standing water in the field, and adult oviposition will be reduced, which may also affect the survival of hatched early instar larvae. 3. Clear weeds. In the spring and winter season before the adults migrated to the rice fields, weeds were cleared and burned, causing them to lose their overwintering sites and directly eliminate pests. 4. Using the characteristics of phototaxis of rice water weevil, black light is set to seduce; killing fields can be set, and the eggs can be integrated into the eggs at night and then eliminated. Second, chemical prevention and control of adults: 28% hypertonic rice Lefeng EC 750 ml per hectare, watered 1500 times liquid spraying. Controlling larvae: 5% insecticidal double granules are uniformly applied at 15 kg per hectare.
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