Seasonal Distribution of Damping–off and Root Rot Pathogens of Sugar Beet and Their Chemical Control

The Seasonal distribution of damping off and Root rot pathogens in different regions from Ninavaha province showed the existence of Pythium debaryanum Hesse and P. ultimum Trow during November until the end of February, while the existence of the last species extende to march and April. Another two isolates of Rhizoctonia solani Kuhn were found during the months of March, April, May and June while the second isolates Phoma betae (Oud.) Fr noticed during February, March, April, May and June. Fusarium solani Mart. was also found during the period extended from October until June, While the Macrophomina phaseolina Tassi appeared during Feb. until June. The Sugar beet variety Trible and Desprez were less Susceptible to previous Pathogens in comparison to Semirave and Ovata Variety. The chemical control showed that Tecto, Rovrin, Rhizolex and Benomyl exhibit a good inhibition effect on mentioned pathogens where as Ridomil-5G worked only effective on Pythium sp. The mixture of Ridomil and Benomyl showed also a superia effect in controlling the sugar beet pathogens.