Investigation of Biological Control of Dodder (Cuscuta monogyna Pers.) by a Strain of Fusarium oxysporum

Eastern dodder is an obligate parasite of many orchard and ornamental plants which has caused extensive damages to them and city landscapes, in recent years. In order to control this parasite biologically, a research was done during 2010-11. Infected tissues of dodder were collected from fields and the city landascapes of Mashhad. One strain of Fusarium oxysporum which was identified with identification key was selected as the best strain and applied on dodder after its connection to the host in three experiments which were conducted using completely randomized designs in greenhouse. In these experiments of the effects of different concentrations of spore suspensions (104, 105, 106 and 107 spores ml-1), various dew periods (0, 6, 12, 18 and 24 hours) and host domain were investigated. Results indicated that the pathogenicity of isolate increased with increasing spore concentration. Therefore, the concentration of 107 spores ml-1 caused 20 percent reduction in dry mass of dodder. Increasing length of dew period caused more diseases. The result of the experiment showed the most severe pathogenicity and 32.9 percent reduction in dodder mass, in more than 18 hours of dew period. Consequently, it can be inferred that this strain has the potential ability of controlling the dodder.