Currently, chitosan has been popularly used to trigger immune system in many crop species for plant disease
protection. This study aimed to determine chitosan effect on controlling dirty panicle disease and affecting on rice yield.
The experimental design was a split-plot in Randomized complete block with 2 conditions (inoculated and non inoculated
rice plant) as main plot and 3 application methods (chemical fertilizer in combination with chitosan, chemical fertilizer
alone and no both chemical fertilizer and chitosan) as sub plot. Pot experiment was conducted in an open greenhouse
during March to June 2012. The results were revealed that all studied traits of inoculated and non inoculated rice plants
applied with various application methods were not significantly different. Application of chemical fertilizer in combination
with chitosan did not significantly differ from application of chemical fertilizer alone on leaf greenness, plant height, dry
matter, grain yield and panicle numbers but significantly differed from those unapplied both chemical fertilizer and
chitosan. However, seeds of dirty panicle disease were significantly affected by various application methods, the lowest
numbers were obtained from application of chemical fertilizer in combination with chitosan whereas no application of both
chemical fertilizer and chitosan showed negative effect on controlling dirty panicle disease in both inoculated and non
inoculated rice plant. From this present study it might be explained that it is possibly to spray chitosan to rice plants for
controlling dirty panicle disease caused by fungi pathogens.