除草剂胁迫对空心莲子草叶甲种群的影响及应对策略

为探讨除草剂胁迫对空心莲子草叶甲种群的影响,寻求合理施用除草剂,有效保护叶甲,提高其控草效果的应对策略,利用叶片残留法测试了在草甘膦、农达、水花生净与35%苄·丁可湿粉等除草剂胁迫下空心莲子草叶甲卵孵化率,幼虫、成虫存活率以及蛹羽化率。结果表明被测试的4种除草剂均不同程度地降低空心莲子草叶甲卵孵化率,幼虫与成虫存活率及蛹羽化率,特别是水花生净28.0、35.0 g/L两种浓度处理,35%苄·丁可湿粉4.0 g/L浓度处理显著降低卵孵化率;农达13.4 g/L浓度处理显著降低1龄前期幼虫存活率,农达40.1 g/L与 53.4 g/L两种浓度处理显著降低2龄前期幼虫存活率;水花生净28.0 g/L浓度处理显著降低3龄前期幼虫存活率;草甘膦97.6 g/L与 122.0 g/L浓度处理、农达26.7 g/L与66.8 g/L浓度处理、35%苄·丁可湿粉2.0 g/L浓度处理显著降低后期蛹的羽化率;35%苄·丁可湿粉1.0 g/L浓度处理显著降低羽化后3 d雌虫的存活率。除草剂除直接杀死空心莲子草叶甲,降低其种群数量外,使叶甲失去食物与避护所,快速地引起叶甲种群崩溃。建议合理施药,并在施药时,随机留若干小斑块不施药,保护叶甲,可望提高其田间控草效果。

Effects of herbicides stress on the population of alligator weed flea beetles, Agasicles hygrophila (Col.: Chrysomelidae) and corresponding strategies

To understand the effects of herbicides stress on the population of Alligator Weed Flea Beetles, Agasicles hygrophila and find corresponding strategies that are herbicides applcation correctly and protection A. hygrophila effectively against herbicides which would improve the biological control for alligator weed, Alternanthera philoxeroides, The hatching rate of eggs, survival percentage both larvae and adults and eclosion rate of pupae of A. hygrophila against herbicides stress, which were glyphosate, Roundup, 14% metsulfuron CFC imidacloprid EC and 35% benzyl. Ding WP stresses, were tested by the leaf residue method. The results showed that 4 kinds of herbicides mentioned above decreased the hatching rate of eggs, survival percentage of both larvae and adults and emergence rate of pupae of A. hygrophila at some way. Specially, the hatching rate of eggs falled significantly against 14% metsulfuron CFC imidacloprid EC of the 28.0,35.0 g/Lconcentrations and 35% benzyl. Ding WP of 4.0 g/Lconcentrations stresses; The survival rate of both 1^st and 3^rd larvae in early stage droped markedly under Roundup of concentrtion 13.4 g/L and 14% metsulfuron CFC imidacloprid EC of concentrtion 28.0 g/L stresses. A marked decline on the survival rate of 2^nd instar larvae in later stage was observed in Roundup of the concentrtion 40.1 and 53.4 g/L stresses. Glyphosate which tested concentration were both 97.6 and 122.0 g/L, Roundup which tested concentration were both 26.7 and 66.8 g/L and 35% benzyl. Ding WP which tested concentration was 2.0 g/L suppressed obviously the emergence rate of pupae in later stage of A. hygrophila. The survival rate of female adults after 3 days eclosion was decreased significantly under 35% benzyl. Ding WP of 1.0 g/L concentration stress. It expressed the information that herbicides could decreased the number of the population by killing the indiviuals of A. hygrophila directly and could destroy the population of leaf beetles quickly by damage their comestible host plants and habitats in short time. It is suggested that herbicides should be equitable application and recommend keeping some small patches free from herbicides to protect A. hygrophila. It is hopeful to improve the biological control effect of A. hygrophila on alligator weed.