Winter plowing and winter plowing after pulling cottonwood to earth before freezing can not only ripen the soil, improve the ability to store rain and snow, but also is an important measure to prevent and treat cotton bollworm. Winter is the weak link in the life history of the cotton bollworm. At this time, the prevention and control measures can achieve a multiplier effect. The bollworm is wintering in the soil with earthworms, and the depth is no more than 10 centimeters. The top layer is more than 6 centimeters. It was observed that adults could not emerge from the soil within 10 cm of the soil. Winter plowing depth is generally about 20 centimeters, so that winter plowing can turn some insects into deep soil, so that it can not be feathered in the second year. At the same time, winter plowing can also turn some insects on the ground surface to be frozen or eaten by birds and beasts. Winter ploughing can also destroy most of the diplodents of the cotton bollworm, so that adult worms cannot be domesticated properly. According to the comparison of pre-winter and post-winter surveys, winter plowing and winter plowing have resulted in a mortality rate of about 80%, and only plowing and non-irrigation, and the mortality rate of pupae is about 65%. The mortality rate is about 45% without tillage or irrigation. According to years of investigation and analysis, there is a positive correlation between the size of the overwintering base and the occurrence of the first generation of cotton bollworms in the second year, that is, the greater the overwintering base number, the more the first generation of cotton bollworms in the wheat field. Therefore, grasping the prevention and control of the overwintering period and reducing the overwintering base number is also of great significance in controlling the occurrence of the second year of the cotton bollworm. Practice has shown that not only cotton fields should be plowed during the winter, but other daylight areas should also be plowed in winter because other crops also have bollworms and overwintering pests. Therefore, the larger the ploughing area, the better the control effect. Pouring water after cultivating in conditional conditions can increase the winter mortality rate of H. armigera.
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