Abstract:
An in vitro experiment and a pot experiment were conducted to find out the variation in host range of ten
selected isolates of Rhizoctonia solani infecting cotton seedlings. Fourteen crop species commonly grown
in Bangladesh were tested in the experiments. The crop species were rice (Ory=a sativa), wheat (Triticum
aestivurn'[; maize (Zea mays), jute (Corchorus capsularisi, mungbean (Vigna radiataj, grasspea (Lathyrus
sativuss, lentil (Lens culinarisi, bush bean tPhaseolus vulgaris), chilli (Capsicum annunn, cauliflower
(Brassica oleracea var botrytiss, carrot (Daucus carota], boulegourd (Lagenaria secerariai, potato
iSolanum tuberosum'[ and sesame (Sesannmi indicumi. Variations were found in their pathogenicity on
cotton seedlings and on 14 other crop species causing damping off and seedling mortality All 14 crop
species tested in the study were found susceptible to highly susceptible to the isolates of R. solani but their
susceptibility was variable. The isolates caused averages of 22.33 to 52.67% seedling mortality. The
maximum seedling mortality was found in bushbean, which was followed by chilli, bottlegourd,
rnungbean, jute, grasspea, cauliflower and sesame showing 52.67, 48.66, 45.06, 41.98, 41.98, 37.66, 37.0 I
and 34.99% mortality, respectively. The lowest seedling mortality was found in maize preceded by rice.
