Rice blast caused by Pyn'cularfa oryza. is one of the most important fungal
diseases on rice crop in the world. Pyrrcufaria oryza, Heiminthosporium oryza,
Afternarfa alternate. sfemphyir‘um sp. and Aspergr'iius sp. were isolated from leaves
and panicles from the two tested cultivars (Giza 171 cv. and Sakha 101cv.) during the
two tested seasons (2004 and 2005). These fungi were isolated most frequently from
Giza 171cv. compared with Sakha101cv.
Laboratory tests were performed to examine the sensitivity of P. oryza to Four
compounds at different concentrations. The results obtained from in vitro tests
indicated that, P. oryza was differ in sensitivity to the tested compounds. Fuji~one
was the most toxic to mycelial growth of the fungus (ECso = 10.0 uga.iiml}, followed
by Hinosan (En = 21.0 uga.i fml), followed by Beam (E059 = 30.8 uga.irml) and the
Neemix (E050 = 63.0 uga.i!ml). Field experiments were conducted to evaluate of five
treatments for control rice blast disease during two tested seasons under natural
conditions. The results indicated that all the tested compounds reduced infection
and severity on leaves and panicles in two tested cultivars (Sakha 101cv. and Giza
171w.) compared with the untreated control. Also, these treatments increased grain
and straw yield of rice crop. The best results was obtained by Beam treatments,
Fuji-one, Hinosan, respectively. The Plant-Guard treatment was the least effective,
while Neemlx gave an intermediate effect.