Corn cultivars, Asteria miliataris, are new pests that began to occur in the 1980s. With the widespread implementation of the wheat-maize double cropping system in China, the depth and number of ploughing and returning crops have continuously decreased, in Hebei Province, Henan Province, and Shandong Province. It has become increasingly serious. Corn cultivating Asteria graminis mainly damages corn, wheat, sorghum and other grass crops and weeds. It occurs in China's North China region for 3 generations a year, and mainly affects summer corn from mid-June to early August. It is the second generation of pests. .
There are many special places for corn ploughing. The first is that the pests are very small and adults are only a few millimeters long. Both the larvae and the adults are not active, but their nymphs and female adults can be densely packed on the stem base, roots and sheaths near the surface of corn seedlings. The damaged leaves and stems of plants are yellowed, the lower leaves are dry, and they are short and thin, showing symptoms similar to lack of water and fertilizers. In severe cases, the whole plant withered and died and could not be seeded. When diagnosing, open the topsoil or pull out the plants and carefully observe the stem base and roots. The second is that we often hear that scale insects damage fruit trees and trees, and do not endanger annual crops. Corn cultivars are the ground pests of eggs in female worm oocysts that attach to corn roots in the field, corn husks, weeds, or soil. The third is that corn cultivars of the second instar nymphs and adults of the sunflower plague are dressed in a layer of white wax powder. The female adults are reddish-brown, without wings, and the male adults are dark brown and small. Having wax powder is the cause of more difficult drug use by scale insects, but 1st instar larvae do not secrete wax powder and are relatively lively, which is a critical period for chemical control, but the second generation 1 instar worm period is only 8 to 10 days.
The following measures should be taken to prevent and treat corn cultivars: The first is to properly control the wheat-maize rotation area, change to dicotyledonous crops such as cotton, soybean, and peanut; the second is to plant insect-resistant varieties; and third, to strengthen cultivation and management. After crops such as wheat and corn are harvested, the crops shall be ploughed in time and taken out of the field. The organic fertilizer, phosphorus and potassium fertilizers shall be added to promote the development of the roots of the maize; timely cultivating and weeding shall be performed; the maize shall be watered in case of drought and kept in time. Soil moisture is suitable; wheat fields should be timely winter irrigation; four is chemical control. The 35% carbofuran seed coating agent can be used for coating treatment according to the seed amount of 2% to 3%. From late June to mid-July, 48% of chlorpyrifos (Loss Ben) EC or 50% phoxim EC 800 to 1000 times were used to water the roots of maize seedlings before corn cultivars.
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