Effects of pH, chelating agents and calcium on root and crown rot of hopbush caused by Fusarium solani

One of the most important problems of the hopbush plant is root and crown rot disease in Khuzestan province. The major important pathogen of this disease is Fusarium solani in this province. In greenhouse, the effects of various levels of soil pH ( 6 and 8 ), chelating agent EDDHA (0, 10 and 20 mmol/L) and calcium (0 and 12 meq/L) on disease severity caused by F.solani were determined through measurement of fresh and dry weight of aerial and underground parts of plants. Results indicated that there was a statistical significant difference in the effects of different levels of EDDHA in 2 used pH, but there was not any significant difference in characters which evaluated between 10 mmol/L and 20 mmol/L of chelating agent at both pH. Addition of EDDHA at 10 and 20 mmol/L concentrations reduced the disease severity 40% and 33.3% respectively at pH=6; and 13.3% and 6.7% at pH=8. On the other hand, there were significant differences in the effects of different levels (10 and 20 mmol/L) of EDDHA when compared with no using EDDHA. In other experiments the effects of calcium and EDDHA (10 and 20 mmol/L) on the same characters were studied. Results revealed that there were significant differences between the effect of Ca and EDDHA levels (10 and 20 mmol/L) and other treatments. Applied of Ca+EDDHA levels (10 and 20 mmol/L) led to disease severity reduced to 6.6%. Also results revealed no significant differences between the effects of applied levels of EDDHA and Ca (12 meq/L) in pH=6. Moreover, results indicated that there was significant differences between the effects of different levels of EDDHA (10 and 20 mmol/L) and Ca (12 meq/L) when compared with the results of applying no chelating agent and calcium.