Effect of VA Mycorrhiza on Root Disease (Pythium aphanidermatum and Meloidogyne incognita) in Tobacco

The interaction studies between five VAM fungi, i.e., Glomus mosseae, G. fasciculatum, G. constrictum, Acaulospora laevis and damping-off root rot pathogen (Pythium aphanidermatum) on tobacco (Nicotiana tabacum L.) seedbeds revealed that all the VAM fungi colonized the roots efficiently within 30 days of inoculation. However, the per cent colonization was higher in the seedlings inoculated with G. fasciculatum. The per cent disease severity in 30 day old seedlings was significantly less in treatments with VAM fungi compared to non-mycorrhizal treatment. The impact of VA-mycorrhizal fungi i.e., Glomus mosseae, G. fasciculatum, G. constrictum, Acaulospora laevis and root-knot nematodes on tobacco plants and the possibility of reducing the harmful effects of rootknot nematodes using VAM fungi, was carried out in pot experiments. The VAM fungus G. fasciculatum significantly increased VAM infection of tobacco plants infected or not infected with nematodes, whereas Meloidogyne incognita significantly reduced them, Mycorrhizal infection percentage and number or galls were affected by variation in mycorrhizal strain. The results indicated that the use of G. fasciculatum as a biocontrol agent is a promising technology for tobacco production.