The sap and heart wooden stakes of Acacia nilotica var. indica, after seasoning and castor bean (Ricinis communis) oil application for exposure to workers of the termites, Odontotermes obesus (Ramb.), were placed in soil pits in completely randomised design with three replications. In each of seasoning and oil application, per cent weight loss of the wooden stakes were recorded and statistically analysed. Minimum per cent weight loss of sap and heart wooden stakes was observed in maximum period of seasoning (100°C for 15 days in oven drying and 60 days in sun drying method) and highest concentration of castor bean oil (20%) by vacuum pressure application. These results are discussed in relation to seasoning and castor bean oil application for wood protection against subterranean termites.

The potential effects of plant derived oils on survival of dampwood termite (Zootermopsis augusticollis) workers was explored on western white pine sapwood blocks. All of the oils rapidly affected protozoa in the hindgut of termite workers and protozoa loss was closely followed by worker mortality. The effects were most rapid with wood treated with Neem, Eucalyptus or Jatropha oils, but mortality also occurred within 7 days with workers exposed to blocks treated with Jojoba or linseed oil. The results illustrate the relatively high sensitivity of dampwood termites to these types of treatment and suggest the potential for natural product control of this termite species.

The study assessed the effect of jatropha, linseed, eucalyptus, neem and jojoba oils on protection of three wood species (Acacia nilotica, Dalbergia sissoo and Pinus wallichiana) against termite attack by Odontotermes obesus. Conditioned and pre-weighed blocks of each wood species were vacuum-pressure impregnated with a 15% concentration of the oil-ethanol solutions. Resistance of treated and untreated wood against termites was tested under laboratory as well as field conditions using choice and no-choice tests. Oil treated wood showed significant reductions in weight loss compared to control treatments. Complete termite mortality was recorded for all oil treatments except eucalyptus oil. Linseed oil showed good results in each treatment in terms of feeding resistance as well as mortality of termites followed by neem, jatropha, jojoba and eucalyptus oil. The lower weight losses were found in both choice and no-choice field tests for linseed oil treated Dalbergia sissoo while untreated Pinus wallichiana sapwood had the greater weight loss. It was observed that the oil retention was significantly more in sapwood than in heartwoods. The retention of oils justified that wood with high oil retention showed more resistance against the termite except eucalyptus oil treatment of Pinus wallichiana.

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