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【目的】针对由Bt棉花和玉米构成的华北农田景观,探讨不同寄主作物对棉铃虫Helicoverpa armigera越冬抗寒的影响。【方法】2013年在河北廊坊科研中试基地的作物田中将棉铃虫幼虫接到Bt棉和玉米上,比较取食不同作物后棉铃虫的化蛹率、存活率和越冬蛹羽化率;在室内控制条件下分别用棉蕾和鲜玉米粒饲喂棉铃虫幼虫。测定滞育蛹和非滞育蛹的鲜重、干重、以及脂肪、糖原和低分子物质含量等指标,比较取食不同作物后棉铃虫的抗寒能力。【结果】取食玉米的棉铃虫滞育蛹干重(117.5 mg)、脂肪含量(457.2μg/mg DW)以及海藻糖浓度(86.45μg/g)均显著高于取食Bt棉的棉铃虫滞育蛹干重(56.6 mg)、脂肪含量(239.6μg/mg DW)以及海藻糖浓度(13.87μg/g);取食玉米的棉铃虫冰点(-10.2℃)显著低于取食Bt棉的棉铃虫冰点(-6.5℃)。【结论】结果表明取食玉米更加有利于棉铃虫越冬。据历史数据,近年来玉米种植面积不断增加,这将提高棉铃虫成功越冬比率,对棉铃虫种群扩张起到促进作用,因此注重玉米上棉铃虫的防治尤为重要。
【Objective】 The objective of this study was to investigate the effects of different host crops on the overwintering and cold resistance of Helicoverpa armigera against Bt cotton and corn in North China. 【Method】 The bollworm larvae were exposed to Bt cotton and maize in the midfield of the pilot plantation in Langfang, Hebei Province in 2013. The pupation rate, survival rate and overwintering pupae eclosion rate of H. armigera were compared after feeding on different crops. Cotton budworm larvae were fed with cotton buds and fresh corn, respectively, under controlled conditions. The fresh weight, dry weight, contents of fat, glycogen and low molecular weight of the diapause pupae and non-diapause pupae were measured, and the cold resistance ability of H. armigera was compared after feeding on different crops. 【Result】 The results showed that the diapause pupa dry weight (117.5 mg), fat content (457.2 μg / mg DW) and trehalose concentration (86.45 μg / g) of cotton bollworm fed corn were significantly higher than those of cotton bollworm fed with Bt cotton (56.6 mg), fat content (239.6 μg / mg DW) and trehalose concentration (13.87 μg / g). The freezing point (-10.2 ℃) of cotton bollworm fed corn was significantly lower than that of cotton boll fed with Bt cotton Freezing point (-6.5 ℃). 【Conclusion】 The results show that feeding corn is more beneficial to the winter bollworm. According to historical data, corn planting area in recent years continues to increase, which will increase the success rate of overwintering cotton bollworm, bollworm population expansion has played a catalytic role, so pay attention to corn bollworm prevention and control is particularly important.