Abstract

Forest tree species have wide application and usage including bioremediation to reduce pollution, conservation of biodiversity, to meet rural and industrial demand, preserving valuable germplasm and wasteland development programme. Diseases caused by nematodes have just begun to recognise as a significant forestry problem. Nematode damage, being density dependant one, becomes visible only when nematode population exceeds critical threshold of economic damage. Information on disease and nematode population dynamics in natural forest stands in Tamil Nadu is quite scanty. Therefore, realizing the importance of nematodes in forest plantation, a study to assess the temporal pattern of plant parasitic nematodes associated with Red Sanders, Pterocarpus santalinus plantation was carried out during June' 04 to June' 05 at Sennamalaikaradu. Mettupalayam. Coimbatore. The plantations was divided into four quarters as A, B, C and D and in each quarter 5 composite soil core and roots were collected from 4 trees of 20 years old plantations at 60 cm depth at a distance of 90 cm from the tree base at monthly intervals to observe nematode population. The data on weather parameters were also collected from the Farm Observatory of Forest College and Research Institute, Mettupalayam in order to find out its influence on nematode reproduction and multiplication. The observations recorded for a period of one year from June' 04 to May’ 05 showed the presence of soil and root population of parasitic nematodes viz., Helicotylenchus dihystera, Hoplolaimus seinhorsti, Meloidogyne incognita and Tylenchorynchus mashoodi on Red Sanders (P. santalinus) plantation. In soil the population of H. dihystera and H. seinhorsti were found to be maximum in number i.e., 35.2 and 14.6 per 200 g soil, respectively during the month of October' 04 followed July’ 04 and August' 04 due to receipt of heavy rainfall ranging from 45.0 to 233.3 mm during these months. Regarding root, the population of H. dihyslera was 8.79 per 5 g root and that of H. seinhorsti was 7.3 per 5 g of root during the month of October’ 04.

Keywords: Red sander, nematode population, temporal pattern