PATHOGENICITY TEST OF PATHOGENIC FUNGI ASSOCIA TED WITH Dalbergia sissoo Roxb. DIE-BACK

Abstract

Shisham is an important forest tree in Pakistan has many uses such as furniture wood, building timbe', and fuel wood etc. In recent few years this tree is facing severe attack of dieback and decline, which calise 5-95% loss of trees especially in linear plantation along road site, forest site and water channels. Symptoms of dieback in present studies were recorded on roots, collar portion, branches and leaves. Plants of all ages we re facing this die-back problem and dying this problem is getting more severe day by day, however actual cause of this problem is still not known. Pathogenicity of pathogenic fungi which were Fusarium oxysporum, Fusarium solani, Macrophomina phaseolina, Botryodiplodia theobromae, Rhizoctonia solani, done was carried by the mother cultures of Pathogenic fungi. These fungi were isolated and identified from the diseased specimens of Shisham (Dalb ergia sissoo roxb.) including root and stem-ba rk. The sampl es were co llec ted from different parts of Punjab at different locations like Forest site, Canal site, Road site and also site depending on Farmer's field according to severity scale. For purification and reiso lation of pathogenic fungi PDA media was used. On inocul ation with Fusarium so/ani, Fusarium Oxysporum, Macrophomina phaseolina, Botryodiplodia theobromae and Rhizoctonia solani to the young plants of Shisham the maximum mortality was shown by the Fusarium spps. As percentage presence of Fusarium spps were maximum in the samples and Pathogenic ity results also showed the maximum mortality rate on plants .Fusarium solani showed more mortality rate as compare to Fusarium oxy.sporum by showing ye llowing of leaves and wilting. Shedding of leaves starts from the top and move downwards at the last stages the branches also dried .Botryodip/odia theobromae showed the minImum mortality rate where as Macrophomina phaseolina and Rhizoctonia so/ani shows almost same mortality. Fusarium was isolated from the all four sites of sampling and all treatments done by Fusarium showed that may be the Fusarium is the causal agent of Die back. On the reisolation of diseased plants maximums Fusarium spp were isolated besides others. Results indi cate that Fusarium so/ani and Fusarium oxy.lporum should be consider a causative and destructive agents of Shisham Dieback.