| Bemisia tabaci(Hemiptera:Aleyrodidae)is an important agricultural pest in the world.It is distributed in many countries and regions,causing serious economic losses to agricultural production around the world.In this paper,we studied the biotypes of Bemisia tabaci in Ningxia,identified the biotypes of B.tabaci in the three representative regions of Ningxia.The population dynamics of Bemisia tabaci on tomatoes and cucumbers in greenhouses were investigated;studied the control effects and the best methods for the use of different yellow plates,and carried out the monitoring of Bemisia tabaci resistance in Yinchuan region.Firstly,we screen for 21 insecticides that are used to measure the indoor virulence,and selected 11 pesticides for field spray efficacy test and 5 for field Irrigation efficacy test at last,just to getting a comprehensive basis of effective and sustainable prevention of Bemisia tabaci.The main results are summarized below:1 Using PCR amplification technology combined with mtDNA COI gene sequence analysis,the biotypes of Bemisia tabaci in three regions of Ningxia were identified.The identification results showed that the biotypes of B.tabaci in the three areas of Shizuishan,Wuzhong and Yinchuan belonged to type Q.Through the investigation of the population dynamics of Bemisia tabaci on tomatoes and cucumbers in the greenhouse of Yinchuan,the occurrence of Bemisia tabaci in tomato in spring began in May and occurred in June.The incidence of Bemisia tabaci on cucumber in autumn was mainly concentrated in October to December.The highest peak was reached in mid-November.The eggs,nymphs and adults of Bemisia tabaci were the most abundant in the upper leaves of tomato plants,followed by the middle leaves and the lower leaves.2 Monitoring the population resistance of Bemisia tabaci in the four representative regions of Yinchuan in 2017 against five insecticides.The results showed that Bemisia tabaci field populations had different degrees of resistance to the 5 agents.The resistance to avermectin was 1.4-6.9 times,and the resistance to imidacloprid and nitenpyram was 5.9-14.0 times,respectively.From 8.0 to 18.0 times,the resistance to beta-cypermethrin and chlorpyrifos was 99.1 to 159.8 times and 41.5 to 51.2 times,respectively.3 Using four different types of yellow board for trapping and killing of Bemisia tabaci,the results showed that the pheromone yellow board had the best trapping and killing effect on Bemisia tabaci,followed by the ordinary yellow board and the sex attractant yellow board,and the whiteboard showed the poorest ability to attract them.There was a significant difference in the control of Bemisia tabaci adults in the field,and the pheromone yellow board had the best control effect.The trapping of Bemisia tabaci in the yellow board was better at 10 to 16 o'clock in different time periods of the day,and it was best at 12 to 14 o'clock.There is no significant difference in the hanging direction of the yellow board and the trapping effect of Bemisia tabaci.The appropriate suspension method can be selected according to the production needs.4 The indoor toxicity tests that using 21 pesticides on Bemisia tabaci showed that avermectin had the highest virulence to adults and nymphs of Bemisia tabaci,followed by spinosad,medicarb salts,and chlorothiophene.The five agents of clothianidin and acetamiprid showed high virulence to adults of Bemisia tabaci,and five agents for metsylate,spinetoram,chlorothiazoline,acetamiprid and imidacloprid.The virulence of Bemisia tabaci nymphs is higher.In the field efficacy test of 11 pesticides,avermectin had the best control effect against Bemisia tabaci adults,followed by acetamiprid and pymetrozine.In the control of nymphs,buprofezin had the best control effect.It is acetamiprid,abamectin.In the field efficacy test of five pharmacological agents,thiamethoxam had the best control effect on B.tabaci,with the highest systemic uptake and longest potency,followed by imidacloprid,acetamiprid,nitenpyram,and azadirachtin. |
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