Effects Of Insecticides On Cyrtohinus Lividipennis (Reuter) (Hemiptera: Miridae), A Predator Of Nilaparvata Lugens (St(?)l) (Homoptera: Delphacidae)

The brown plant-hopper(BHP) Nilaparvata lugens(St(?)l) was an important insect on rice in most regions of China.It broke serious these years,and caused severe damage to rice production.Cyrtohinus lividipennis(Reuter) was a predator of BHP,and played an important role in nature controlling BHP.Insecticides were main measures for controlling BHP for a long time,but it irrational using killed some important natural enemies,such as C.lividipennis.Consequently,for providing basic theory for using pesticides and IPM,we evaluated the safety of organophophates,carbamates,pyrethiods,neonicotinoids,phenyl pyrazole perivatives,IGRs and antibiotics insecticides to C.lividipennis,and tested the effects of imdacloprid,thiamethoxam on survival,oviposition and predation of C. lividipennis with rice seedling,and effects of buprofezin on oviposition of C.lividipennis adults.Toxic film method was used for testing toxicity of 29 insecticides to adults and buprofezin to nymphs of C lividipennis.The results showed that the LC₅₀ values of fipronil, microemulsion,nitenpyram,thiamethoxam,isoprocarb and promecarb were 0.201 - 1.000 mg a.i./L,they were highly toxic to adults(Rankâ…£).The LC₅₀ values of silafluofen, etofenprox and cycloprothrin to adults and buprofezin to nymphs of C.lividipennis were more than 160.0 mg a.i./L,they were safe to C.lividipennis(Rankâ… ).Effects of 14 insecticides in 7 groups on adult survival of C.lividipennis were tested by rice spray method.The results showed that buprofezin and avamectine was caused less than 11%mortality at 1 day after treatment,they were safe to adults of C.lividipennis(Rankâ… ).While carbosulfan,fipronil,thiamethoxam and imidapcloprid caused 70.0%-100% mortality at 4 - 10days after treatment,they were moderate toxic or highly toxic to adults (Rankâ…¢orâ…£).Effects of 14 insecticides in 7 groups on nymph survival of C.lividipennis were tested by rice stem dipping method.The results showed that buprofezin was safe to nymphs(Rankâ… ),caused 16.8%mortality.While other tested insecticides killed all nymphs of C. lividipennis(Rankâ…£) except avamectine,which caused 78.6%mortality. Rice spray method explained that tested insecticides had lower toxicity to eggs of C. lividipennis.The hatching inhibition rate of etofenprox,abamectin,silafluofen,isoprocarb, dichorbos and buprofezin were lower than 20.0%,safe to eggs of C.lividipennis(Rankâ… ), while carbosulfan was the most harmful insecticide to eggs of C.lividipennis in treated insecticides,its hatching inhibition rate were 52.24%and moderate toxic to eggs of C. lividipennis(Rankâ…¢).Irrigating to rice roots with 20mL solution containing 100,10,1,0.1,0.01mg a.i./L imidacloprid and thiamethoxam for testing their effects on survival,oviposition and predation of C.lividipennis.The results showed that imidacloprid and thiamethoxam caused more than 92.5%mortality at the rate of 100 and 10 mg a.i./L.These two insecticides have no effects on adult survival at 1,0.1 and 0.01mg a.i./L,but it decreased the number of laid eggs and percents of eggs preyed,and they were lower with their concentration increased.Treated with new adults of C.lividipennis at the rate of 250 mg a.i./L(buprofezin) by toxic film method.The results showed that the eggs of Iaid was decreased at 2 - 4days after treatment,and have significantly difference compared with CK,but it have no effects on oviposition at 0 - 2days,4 - 6days,6 - 8days,8 - 10days after treatment.