Abstract

Termites cause considerable damage to young plantations of Eucalyptus spp. in India, of which E. tereticornis and E. grandis are cultivated in the State of Kerala. This final report of an entomological research project that was conducted from July 1976 to June 1980 contains sections on the literature on termite control in Indian eucalypt plantations, on the evaluation of insecticides and treatment techniques used in Kerala in 1976-80, and on the ecological aspects of the termite problem in eucalypt plantations. Tests were made initially on small plots of E. tereticornis, and the most promising compounds or methods were then retested on a larger scale in the plantation. Both E. tereticornis and E. grandis were found to be susceptible to infestation,and in general 20-80 of untreated experimental seedlings were killed in the first year after planting; mortality varied in different years and localities and was not correlated with rainfall. Termite attacks occurred in almost every month but were most numerous in July-August and sometimes also in April-May. A list is given of the 17 termite species found in the region; not all damaged Eucalyptus spp., and the most injurious were the root-feeders Microtermes obesi Hlmgr., Odontotermes ceylonicus (Wasm.)O. guptai Roonwal & Bose and O. roonwali Bose (which caused lethal damage), followed by the bark-feeders O. redemanni (Wasm.) and O. vaishno Bose. Since these injurious species lived in small underground colonies and did not build conspicuous mounds, their presence often remained unnoticed until seedlings collapsed suddenly after destruction of their roots. Preventive rather than curative treatment is therefore essential. Out of 4 insecticides tested on young trees of E. tereticornis, aldrin and heptachlor were the most suitable, since HCH (BHC) did not give satisfactory protection and chlordane proved phytotoxic. Aldrin, heptachlor and chlordane in dust or liquid formulations gave good protection when applied in the soil of the planting pit or container; container treatment with a liquid formulation was found to be the simplest procedure and gave sufficient protection even after transplanting, without the necessity for additional pit treatment. A dosage of 0.12 g toxicant in 50 ml water for each container measuring 12 X 18 cm is recommended, applied as a drench with a rose can