Soybean charcoal rot disease status and distribution in Golestan province

Charcoal rot, caused by fungal species Macrophomina phaseolina, is one of the most important diseases of soybean in north of Iran and in some years, it causes great damage to the crops. In order to determine the infection in different regions of Golestan province, soybean fields were surveyed during November and December of 2009, and disease incidence (I) and severity (S) via dividing the height of infected stem by total stem height were recorded. Statistical analysis of collected data revealed that there is a significant difference for I and S between regions and fields under study. Results of the mean comparisons using Duncan multiple range test revealed that fields of region Aliabad and Azadshahr regions had the highest and lowest I, with 40 and 0.09 %, respectively. The maximum and minimum values of S was observed in Aliabad and Azadshahr, with 11 and 2.5 %, respectively. The mean value of I in the studied fields was 21.24% and mean severity of disease was 6.7%.