Spodoptera exigua is a lepidopteran noctuidae pest. In the cotton field, larvae feed mainly on the leaf meat, and they also feed on the buds. The leaves of severely damaged plots only have reticular veins and petioles. In recent years, the area of ​​Spodoptera exigua in Yancheng, Jiangsu's coastal cotton area has expanded and the degree of occurrence has increased. On these issues, China Agricultural Resources Online Plant Protector Lao Yao exchanged its features and preventive measures: Occurrence characteristics (1) Miscellaneous food. Spodoptera exigua larvae can harm cotton, corn, soybeans, peanuts, vegetables and other crops. (2) Suddenness and uneven distribution of insects. In the year of Spodoptera exigua, there were more than 100 insects in the cotton field and 1000 replants in the re-emerging areas. In general, the amount of insects in the continuous cotton fields in the east coast is higher than that in the paddy fields in the western China. The fields with poor growth are higher than those with good growth, and those with high salinity are higher than those with low salinity. (3) The hazard is long and the generations overlap. The Spodoptera exigua in some districts of Yancheng City is endangered from late May to mid-September. From mid-July to the end of August, the Spodoptera exigua has a large amount and heavy damage. Long-term coexistence of field larvae with moths, eggs and cockroaches. (1) There are many hosts. The adjustment of planting structure, the development of greenhouse vegetables, and the promotion of light cultivation techniques such as less (free) cultivation provide an ideal wintering ground and food source for Spodoptera exigua, reducing the control effect of agricultural operations on Spodoptera exigua. It facilitates the migration of hazards and reproduction between different hosts. (2) Migration. Spodoptera exigua can survive in winter or move long distances. It has the characteristics of sudden and regional outbreaks. It is difficult to predict and predict, and it is easy to miss the appropriate period of prevention and control. (3) Enhanced drug resistance. For many years, the control of Spodoptera exigua relies on pyrethroids and organophosphorus insecticides. After long-term use, the resistance of larvae is significantly enhanced. The investigation found that the control effect of these two types of drugs on the young larvae of Spodoptera exigua is only about 60%, and the control effect on old larvae is less than 50%. (4) High reproduction rate. The results of indoor rearing of old larvae of Spodoptera exigua in the local cotton field showed that each female laid an average of 104 eggs, the hatching rate of eggs was 82%, the duration of eggs was about 2 days, and it took only 28 days to complete one generation in summer. Spodoptera exigua can explode in the short term. Prevention measures Ploughing and smashing in winter will destroy the wintering grounds of Spodoptera exigua. During the growing season, clean the pastoral, cultivating and weeding, and reduce the beet armyworm spawning sites and suitable hosts. The Spodoptera exigua larvae have a pseudo-dead nature. They can invert the umbrella or spread the film on the ground and shake the plants to drop them and kill them. The Spodoptera exigua larvae are highly resistant to pyrethroids and organophosphorus insecticides and should not be used for the control of these two types of drugs. From the perspective of production applications in recent years, 15% indoxacarb was used as a suspension agent. The 24% Methoxyfenozide Suspension and Emamectin benzoate preparations are effective against Spodoptera exigua larvae and can be alternately used to delay drug resistance. Ffp2 Face Mask,Disposable Masks,Ffp2 Medical Mask,Disposable Face Mask Shaoxing Aladdin Enterprise Co.,Ltd , https://www.xhemostat.com
Recurrence factors