氯虫苯甲酰胺对黑肩绿盲蝽实验种群的影响

采取稻茎浸渍法测定了氯虫苯甲酰胺对黑肩绿盲蝽毒力,利用生命表技术研究了氯虫苯甲酰胺对黑肩绿盲蝽实验种群的影响,为协调水稻害虫的化学防治和生物防治提供参考。结果表明,氯虫苯甲酰胺对黑肩绿盲蝽若虫LC50和LC10分别为83.5mg/L和61.3 mg/L,氯虫苯甲酰胺对黑肩绿盲蝽成虫LC50和LC10分别为64.3 mg/L和39.0 mg/L。氯虫苯甲酰胺对黑肩绿盲蝽若虫和成虫的LC10分别大于和接近于大田使用剂量40mg/L。以大田使用剂量40 mg/L氯虫苯甲酰胺稻茎浸渍法处理黑肩绿盲蝽3龄若虫后,其产卵期、寿命和产卵量降低了4.3 d、3.0 d和22.0粒,与对照相比差异显著,表明氯虫苯甲酰胺对当代成虫寿命与生殖力影响较大;药剂处理后次代种群的成虫前期延长了2.3 d;存活率、平均日产卵量跟对照相比明显降低;种群净增值率、周限增长率、内禀增长率跟对照相比明显降低,分别为21.0(对照63.3)、18.8(对照19.2)、0.16(对照0.22),而种群加倍时间延长为4.3(对照3.2);这些结果表明,在40 mg/L浓度下,氯虫苯甲酰胺能够降低黑肩绿盲蝽种群的增长。

Effects of chlorantraniliprole on experimental populations of Cyrtorhinus lividipennis (Reuter) (Hemiptera: Miridae)

Chlorantraniliprole is a kind of systemic insecticide and also so-called low risk insecticide targeting at the ryanodine receptor.Chlorantraniliprole has been recently registered for controlling the rice insect pests such as rice stem borer,rice leaf roller and rice water weevil in China.In order to investigate its non target effects,we estimated the toxicities of chlorantraniliprole on nymphs and adults of Cyrtorhinus lividipennis(Reuter),an important predator in rice ecosystem,by using the rice-stem dipping method.The rice-stem dipping method has been normally used to estimate the killing effect of the systemic insecticide to rice planthopper.The LC50 and LC10 of the third instar nymphs and newly emerged adults were examined.The estimated LC50 and LC10 on nymphs were 83.5 mg/L and 61.3 mg/L,respectively.Meanwhile,the estimated LC50 and LC10 on adults were 64.3 mg/L and 39.0 mg/L,respectively.These doses were higher or similar to the field recommended dose(40 mg/L) which indicates that chlorantraniliprole is a safe insecticide for natural enemies.However,the outcome from toxicity test does not necessary suggest its safety on C.lividipennis because there still are some negative effects,e.g.,reduced fecundity,adult mating ability.Consequently,we investigated some negative effects by comparing the biological performance of insecticide treated or not treated of C.lividipennis.The insecticides were applied at the third instar nymph stage with 40 mg/L dosage or control.The biological characters of C.lividipennis adults were measured to estimate negative effects.The female pre-ovipositing period,ovipositing period,longevity,and fecundity were measured.These characters were significantly decreased if treated with the field recommended dose of chlorantraniliprole.The pre-ovipositing period were prelonged from 2.3 days to 3.0 days.In contrast,the ovipositing period,female longevity,and fecundity were all significantly reduced.All these changed aspects resulted into the largely reduced population growth rate of C.lividipennis which suggested that chlorantraniliprole could result a negative effect on natural enemies.Furthermore,we also investigated the potential effects of chlorantraniliprole on C.lividipennis offspring.When the 3rd instar nymphs treated with 40 mg/L chlorantraniliprole,F1 generation eggs and nymphs had significantly extended developmental immature stages.In addition,the daily survival rate and fecundity of F1 females treated by chlorantraniliprole were significantly decreased in compared to control.For example,the averaged egg laid by untreated female was 70.5,while it was only 47.6 by treated female.We also estimated the net reproduction rate(R0),finite rate of increase(λ),and intrinsic rates of increase(rm) of F1 generation.All of these parameters of treated individuals were decreased significantly in compared to untreated individuals.Especially,the net reproduction rate(R0) of untreated population was largely reduced from 63.3 to 21.0.The calculated population doubling time(t) was extended from 3.2 d(control) to 4.3 d(treated).These results suggested that C.lividipennis can survive from the directly killing effect of the field recommended dosage(40 mg/L) of chlorantraniliprole.However,the sublethal effect of chlorantraniliprole can result a remarked negative effects on the population growth of.C.lividipennis.These results would provide some evidences to apply chlorantraniliprole to harmony the insecticide and biological control against rice pest insects.