Study On Controlling Dendrolimus Tabulaeformis With Pyroligneous Acid And Insecticidal Plants

Pyrohgr.eous acid is a kind of natural medicament. which has a lot of function. In this experiment the mixture of liquid wood vinegar and ultrasonic extractions made from insecticidal plants have been used as pesticides in the controlling of Dendrolimus tabulaeformis Tsai et Liu larvae. The results shown that those extracts made by supersonic wave extracting apparatus using water as solvent were highly effective to control D. tabulaeformis Tsai et Liu Among those self-made pesticides, the mixture of wood vinegar with the extracts made from Urtica angustifolia Fisch. was the best in the control of D. tabulaeformis Tsai et Lu. The mortality rate of those larvae treated by this mixture was up to 100%. The pesticide containing wood acid and extracts made of Polygonum avicu'are L was also very effective. The mortality of treated larvae was more than 86.6%. The mixture composed of wood vinegar and extracts made of Angelica dahurica (Fisch.ex Hoffm.) benth.et Hook.f. or extracts made of Chelidonium majus L. were also very effective in the control of D. tabulaeformis Tsai et Liu, those larvae treated by those pesticides were more than 86.67% and 60% respectively. The functional mechanism of those self-made pesticides was stomach poison. so they have no side effect on plants.The results from these experiments shown that those compounds which have pest killing effect could be solvated in water, so the extracts solvated in water were more effective than those solvated in ethanol. Using water to extract those poison cornpounds can reduce the cost and increase the economic benefit.Those plants used in the making of pesticides have larger natural resources in our country and they could be easily cultivated.