Effect of Some Microorganisms and Chemical Stimulants on Resistance to Fusarium Roots Rot and on Growth Characteristics of Beans

Abstract

In the last few years, Fusarium solani caused root rot and among different important diseases attacked common beans (Phaseolus vulgaris L.) under the Egyptian climate conditions. The type of Fusarium that causes common bean roots rot has been identified through morphological characteristics on environmental media. Five isolates of Fusarium solani f. sp. phaseoli were isolated from naturally infected bean roots representing different localities of some governorates, was tested pathogenicity to common beans (cv. Nebraska), during summer growing season 2018. Results indicated that isolate which obtained from Derwa (Minia Gov.) was the virulent that induced the disease. Under laboratory conditions, the effect of some microorganisms (Trichoderma harzianum, Trichoderma hamatum, Bacillus subtilis, Pseudomonas fluorescence and Rhizobium leguminosarum biovar phaseoli) and some induceding materials (Salicylic acid, Ascorbic acid and Boric acid) on mycelial growth of the pathogenic isolate of F. solani f. sp. phaseoli. The results showed that treatment T. harzianum compared with other treatments and control plates addition (PDA) medium as sterilized caused the highest decrease in the mycelial growth of the virulent isolate by about (63.62%).Under greenhouse conditions, previous treatments was evaluated in percentage incidence and disease severity Fusarium root rot disease. The results indicate that the previous treatments, whether singly or in combination with rhizobium, reduced the disease by varying degrees. On the other hand, the results indicated that the fungus T. harzianum was the most effective in reducing the percentage incidence and severity of disease by about (13.33 and 11.11%, respectively), while T. harzianum combination treatment with rhizobium gave better and more effective by about (8.89 and 6.67%, respectively) compared with other treatments and control. As well as, such treatments, whether singly or in combination with rhizobium, gave, significant increase growth characteristics by various degrees. While, T. harzianum mixed with rhizobium proved more effective in comparison with T. harzianum singly by about: in Plant height (25 and 34 cm.), number of nodules/plant (15.33 and 22.33), dry weight of nodules/plant (0.015 and 0.028 g), dry weight of root (1.68 and 2.47 g), dry weight of shoot (2.48 and 4.20 g) and nitrogen (N) content (2.14 and 3.18), respectively.