Investigation of possible vesicular arbuscular mycorrhizal associations in prevalent weeds in tea lands of Badulla

A study was carried out to investigate the possible vesicular arbuscular mycorrhizal (VAM) associations in prevalent weeds in selected tea lands of Badulla. Roots of Ageratum conyzoides, Axonopus compressus, Bidens pilosa, Borreria latifolia, Cleome rutidosperma, Drymaria cordata, Eleusine indica, Erigeron sumatrensis and Oxalis corniculata were collected from Wewessa, Spring Valley and Telbedde estates. Colonization percentages and spore counts were calculated using the Grid and Doncaster’s counting disc methods, respectively. Rhizosphere soil of highly VAM associated weeds were tested for soil phosphorous and all weeds were tested for soil pH. The highest colonization percentage was recorded as 60.39% with A. compressus. The highest spore number was counted as 187 per 5 g soil with B. latifolia. The lowest soil phosphorus level was measured as 4.17 ppm with A. conyzoides. There was a systematic moderate positive correlation between, root colonization percentages and soil pH. In conclusion, there was a close association of VAM with selected nine weed species.