Brown Root-rot of Poplars

Abstract

The paper deals with investigations on a new root-rot disease of poplars caused by Fomes noxius in Tarai Central Forest Division, Uttar Pradesh. Disease symptoms are given. Mortality in 1981 and 1976 plantations of Populus deltoides (G-3, D-61, D-67 and G-48 clones) ranged from 7-12 per cent. The disease was found to have established mainly through basal wounds on trees caused by tractor blades during ploughing in between poplar lines for raising agricultural crops though establishment of disease from infected roots of previous crop lying buried in the soil was also observed Incidence of tractor blade injuries ranged from 16-48 per cent on standing crop. The fungus did not spread freely in unsterilized soil in laboratory experiments. Spread of the disease in the plantations was found through contact between diseased and healthy roots of adjacent trees Fomes noxius was found to exist in old mixed plantations. The fungus also produced abundant fruit bodies on stumps of poplars left after felling diseased crops. Control of the disease is recommended by avoiding basal injuries during cultivation of agricultural crop, raising new poplar lines inbetween old lines and isolation of diseased patches by semi-circular trenches.