Experimental results on the preventive effect of wood damaging insects of some extracts from plant materials

Nguyen Thi Bich Ngoc, Truong Quang Chinh

Nguyen Duy Vuong, Nguyen Thi Hang, Le Bach Dang

Forest Science Institute of  Vietnam 

On the basis of Vietnam’s available floral material sources and using prevention experiences for harmful creatures, the Forest Science Institute of Vietnam has conducted research on the evaluation of the preventive effect of wood damaging insects of some active  compounds extracted from Melia azedarach L, Milletia ichthyochtona Drake, Azadirachta Indica A.Juss, Pterocarya stenoptera C.DC var, and Dioscorea cirrhosa. This research aims to provide a scientific basis for expanding possibilities of using biologically active compounds to produce wood preservatives.

Melia azedarach L, Milletia ichthyochtona Drake, and Pterocarya stenoptera C.DC var: are triturated, and then soaked in solvents of water, ethanol, and chloroform. Refine from residues, gain the effective experimental solution. Azadirachta Indica A.Juss is pressed to take oil. Dioscorea cirrhosa is pressed to take Tannin. Azadirachta Indica A.Juss oil is diluted with solvents of diesel and tannin and diluted with a water solvent to test its effect.

Method of effect experiment: Sample of Canarium album Raeusch timber is soaked with experimental solutions, then place into environment where the Coptotermes formosanus is strongly activating in one month period. Evaluate effect of active elements based on how much termites destroy the timber sample.

Active compounds of Pterocarya stenoptera C.DC var, Melia azedarach L which are extracted with water, ethanol, and chloroform all are less effective to forest products harming-termites.

Solutions of oil from Azadirachta Indica A.Juss and tannin from Dioscorea cirrhosa at concentration levels from 2% to 10% respectively gain its effect at average level when using soaking method to handle timber sample (soak for 10 minutes). Concentration level of solutions from above 4%, when soaking into timber sample using soaking method (soak in 24 hours), gain good effect to forest products harming-termites.

Active compounds of Milletia ichthyochtona Drake are extracted with water and ethanol at a ratio of 1:3 and 1:4 (mass of floral materials per mass of solvent) all are effective against termites. Of which, the solution extracted with ethanol is more effective to termites. The active compounds extracted with chloroform solvent is less effective to termites.

Pterocarya stenoptera C.DC var, Melia azedarach L, Milletia ichthyochtona Drake, Azadirachta indica A.Juss, and Dioscorea cirrhosa are used to extract some compounds for experiments which measure preventive ability to Coptotermes formosanus (representative for forest products harming-insects in Vietnam). Experimental results show that Azadirachta Indica A.Juss, Milletia ichthyochtona Drake, and Dioscorea cirrhosa contain active compounds which prevent forest products harming-insects. Active compounds from Azadirachta indica A.Juss, Milletia ichthyochtona Drake, and Dioscorea cirrhosa will be researched to produce preservatives with preventative effect to forest products harming-insects. 

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