Evaluation of Trichoderma spp., Pseudomonas fluorescence and Bacillus subtilis for biological control of Ralstonia wilt of tomato

Abstract

Abstractis the major bacterial disease in tomato, Background: Ralstonia solanacearum which invades the roots of diverse plant hosts and colonizes xylem vessels causing wilt, especially in tropical, subtropical and warm-temperate regions. R.produces several toxins helping it to invade the plant's natural solanacearum defense mechanism. Native isolates of Trichoderma spp., Pseudomonas and can be used as biocontrol agents to control fluorescence Bacillus subtilis the bacterial wilt and combined application of these beneficial microbes can give better results.Bacterial wilt infection in the field was identified by field experts and Methods: the infected plant part was used to isolate in CPG Ralstonia solanacearum media and was positively identified. Subsequently, the efficacy of the biocontrol agents was tested and documented using agar well diffusion technique and digital microscopy. 2ml of the microbial concentrate (10 cfu/ml) was mixed in one liter of water and was applied in the plant root at the rate of 100 ml per plant as a treatment method.It was observed that the isolated spp. AA2 and Results: Trichoderma PFS were most potent in inhibiting the growth of Pseudomonas fluorescence R. showing ZOI 20.67 mm and 22.33 mm, respectively. Digital solanacearum, microscopy showed distinct inhibitory effect on the growth and survival of R.The results from the field data indicated that spp. solanacearum. Trichoderma and alone were able to prevent 92% and 96% of Pseudomonas fluorescence the infection and combination of both were more effective, preventing 97% of infection. Chemical control methods prevented 94% of infection.Results showed the bio-efficacy of the native isolates. The Conclusions: various level of antagonistic effect against shown by all 13 R. solanacearum isolates, including the results shown by native isolates in the field, manifested the promising potential of the biocontrol agents, like and Trichoderma against controlling the bacterial wilt infection. Pseudomonas

Evaluation of the efficacy of Trichoderma and Pseudomonas species against bacterial wilt Ralstonia isolates of tomato (Lycopersicum species)

“…The results could be attributed to the synergistic effect between the combinations of the two microorganisms in this treatment. These results were in harmony with those reported by Yendyo and Pandey (2017) that Trichoderma spp. and P. fluorescence seem to be more effective than treatment using each individual biocontrol agent that has been achieved 97% of (Morsy et al, 2009).…”

“…AA2 and Pseudomonas fluorescens PFS were most potent inhibiting the growth of Ralstonia species and the field study indicated Trichoderma spp. and P, fluorescens alone were able to prevent 92 and 96% of the infection and combination of both were more effective, preventing 97% of infection compared to chemical control methods that prevented 94% of infection (Yendyo and Pandey, 2017). This shows the promising potential of native isolates of Trichoderma spp.…”

“…Soil samples from the rhizosphere of healthy and bacterial wilt infected tomato plants were collected from different fields from Ziway and Meki along the Rift Valley, which is one of the most important vegetable producing areas in the country. Diseased plant samples were selected based on visible characteristic symptom of bacterial wilts (Yendyo and Pandey, 2017).…”

“…(2007), Aliye et al (2008) and Yendyo and Pandey (2017) where they reported that isolates of P. fluorescens had significantly inhibited under the bacterial growth of R. solanacearum under in vitro conditions. The in vitro antagonistic activity of T. asperellum was reported by Narasimha et al (2013) that inhibit the growth of R. solanacearum with inhibition zone ranging from 11 to 27 mm diameter.…”

Memorias del II Congreso de Control Biológico Aplicado

“…Además, se determinó la interacción directa de los antagonistas con el patógeno y la reducción de una enfermedad en progreso, ya que, las plántulas fueron infectadas antes de la inoculación con los antagonistas (Rajeswari y Kapoor, 2018). Esto determina una efectiva colonización de los antagonistas y permite reducir la variabilidad del control de la enfermedad en el campo (Yendyo et al, 2017). Se determinó la capacidad de los consorcios como potentes promotores de crecimiento, debido al incremento significativo en los valores observados.…”