Vesicular-arbuscular mycorrhiza and Trichoderma virdi as deterrents against soil-borne root rot disease of sugar beet

Abstract

The aim of the present work was to study the effects of vesicular-arbuscular mycorrhiza (VAM) and Trichoderma virdi (T. virdi) fungi as deterrents against Rhizoctonia solani (R. solani) and Fusarium solani (F. solani) infections on the growth and quality of sugar beet. Two experiments were carried out in the greenhouse at the Agriculture Research Center, Giza, Egypt, under greenhouse conditions. The results showed that mycorrhizal and T. virdi inoculation significantly restricted the spread of both soil-borne pathogens in the host root tissues. Disease incidence of sugar beet roots was reduced to 6.2 and 5.2% for mycorrhiza with Rhizoctonia and 5 and 4.5% with Fusarium in the 1st and 2nd seasons respectively. Trichoderma with Rhizoctonia inoculation reduced disease incidence to 6.0 and 5.8% and with Fusarium to 5 and 4.3% in the 1st and 2nd seasons, respectively, compared to pathogen (Rhizoctonia and/or Fusarium) alone. In the first and second seasons, respectively, incidence of R. solani infection, in combination with mycorrhiza treatment, was reduced to 6.2 and 5.2%, and to 5 and 4.5% when amended with F. solani. Dual inoculation with mycorrhizal or T. virdi and the pathogen resulted in increasing total fresh and dry weight, nitrogen (N), phosphorus (K) and potassium (P) contents of sugar beet leaves and roots compared to pathogen-inoculated plants. Furthermore, the same treatments increased yield and quality traits of sugar beet (sucrose, total soluble solids and purity percentage). The use of this microbial model system in biological suppression of R. solani and F. solani will sustain the productivity of sugarbeet.