Toxicity and Field Control Effect of Botanical Pesticide Matrine to Mulberry Pests

In order to test the feasibility of using matrine which was extracted from traditional Chinese herb kuh-seng for controlling mulberry pests,a 2% matrine diluted solution was used to conduct indoor toxicity tests and field control trials to a number of mulberry pests.Besides,whether it was safe to silkworm was examined.The results showed that 2% matrine had high toxicity to phthonanadria atrilineata,Euproctis similes,Ascotis selenaria,Spilarctia subcarnea,and Acronicta major.The LC50 to these pest species was 23.55,28.73,28.52,30.71,and 25.61 mg/L respectively.Treatment with its 1 500 times diluted solution to the above 5 pest species caused a death rate of 92.18% ~96.78% in laboratory at 24 h.Meanwhile,Field control with this diluted solution also had satisfactory effect.The pest population reduction rate was 89.81% ~96.00% at 24 h.2% matrine diluted solution also had high toxicity and good control effect to Pseudcdendrothrips mori and Tetranychus cinnabarinu.Treatment with its 1 500 times diluted solution to these two pest species caused a death rate of 95.52% and 98.07% in laboratory and a pest population reduction rate of 90.61% and 92.55% in field at 24 h,respectively.2% matrine diluted solution had relatively lower toxicity to Diaphania pyloalis and Bombyx mandarina.The LC50 to these two pest species was 364.47 and 351.01 mg/L respectively.Treatment with its 1 500 times diluted solution to these two pest species caused a death rate of 3.13% and 3.83% in laboratory and a pest population reduction rate of 18.06% and 8.70% in field at 24 h,respectively.After mulberry trees were sprayed with 2 000,1 500 and 1 000 times diluted solution of 2% matrine,the safety time interval to silkworms was 4,8,and 32 h respectively.After the safety interval,harvesting mulberry leaves for feeding silkworms had no adverse influence to growth and development of the larvae and to cocooning features.Based on these experimental data,it is concluded that matrine has selective pest control effect to mulberry pests.If the dominant pest species are phthonanadria atrilineata,Ascotis selenaria,Euproctis similes,Spilarctia subcarnea,Acronicta major,Pseudcdendrothrips mori and Tetranychus cinnabarinu in mulberry field,one may consider to use matrine for pest control.