Occurrence dynamics and key control techniques of fall armyworm Spodoptera frugiperda in maize field of Xingping City,Shaanxi Province,China
To clarify the population dynamics of fall armyworm Spodoptera frugiperda in maize fields in the Guanzhong area of Shaanxi Province and to screen suitable insect-resistant maize varieties and ef-fective control insecticides,the population dynamics of S. frugiperda was monitored by using sex phero-mone traps in the maize field in Xingping City during 2020—2022. In addition,the damage caused by S.frugiperda to eight maize varieties cultivated in Shaanxi Province were investigated based on the five-scale assessment of plant damage and the number of egg masses. Meanwhile,the toxicity of seven pesti-cides to eggs and 3rd-instar larvae of S. frugiperda and their field control efficacy were investigated. The results showed that adult S. frugiperda began to emerge in Xingping City in mid-June in 2020 and 2021,and in late July in 2022,peaked from late August to late September,and disappearing in early Novem-ber during 2020—2022. The number of moths trapped was highest in 2021,with 212 individuals per trap,compared to 2020 and 2022. Oviposition of S. frugiperda exhibited selectivity among maize variet-ies and leaf positions,with significantly fewer egg masses laid on Zhengdan 958 than on Huanong 887,and on upper side of leaves than on the underside. Among the maize varieties tested,Qinlong14 and Zhengdan 958 showed less damage,with mean damage ratings lower than 2.0 at 25-35 d after planting,while Zhengda 12 and Jiyuan 1 suffered the heaviest damage,with ratings between 2.5 and 3.4. Of the insecticides tested,5.7％ emamectin benzoate exhibited the strongest toxicity against S. frugiperda eggs,with an LC50 of 5.03 mg/L,followed by 60 g/L spinetoram and 10％ chlorfenapyr,with LC50 values rang-ing from 25.81 to 32.27 mg/L. Furthermore,5.7％ emamectin benzoate,60 g/L spinetoram,and 50 g/L lufenuron exhibited stronger toxicity against larvae,with LC50 values ranging from 0.14 to 0.63 mg/L. The field control efficacy of 5.7％ emamectin benzoate,60 g/L spinetoram,and 50 g/L lufenuron at days 3-10 after application was optimal,ranging from 92.34％ to 99.12％,followed by 200 g/L chloran-traniliprole and 150 g/L indoxacarb,with control efficacy ranging from 85.67％ to 92.09％ . These re-sults suggest that maize varieties Qinlong 14 and Zhengdan 958 planted in Shaanxi Province exhibit some resistance to S. frugiperda,and 5.7％ emamectin benzoate and 60 g/L spinetoram demonstrate the highest toxicity to eggs and larvae of the local population,as well as the best control effect in the field.
Spodoptera frugiperdapopulation dynamicsmaize varietyresistanceinsecticidetoxicityfield control efficacy
万方数据
维普
