Biological Control of Green Bean Damping-off Disease Caused by Rhizoctonia solani by Streptomyces parvulus Strain 10d

Abstract

T HIS STUDY aimed to evaluate the efficacy of applying spores and chitinase enzyme of Streptomyces parvulus strain 10d in biological control of damping-off disease caused by Rhizoctonia solani in green beans (Phaseulus vulgaris) and compare it with Rhizolex fungicide application. Five seeds of green bean were sown in plastic pots, filled with either sterilized or non-sterilized soils, infested with R. solani inoculum (5g/kg soil). Pots were kept in the greenhouse for 45 days from sowing. Pre-emergence damping-off was recorded 15 day from planting and post-emergence damping-off and survival rate were recorded 30 days from planting. Plants growth characteristics were recorded 45 days of sowing.Results showed that Rhizolex treatment had the best survival rate and lowest root-rot severity (79 and 25%), followed by crude enzyme treatment (76 and 25%), then spores' treatment (75 and 27%, respectively), in infested and non-sterilized soils.For plant growth characteristics, in infested and non-sterilized soil, spores' treatment had the best effect on plant height (41.5cm), followed by crude enzyme (39.5cm) and Rhizolex treatments (34.6cm). Numbers of leaves/plant were the highest in Rhizolex (17), followed by spores (15) and enzyme treatments (14). Numbers of pods/plant were 14 in Rhizolex treatment and 11 in crude enzyme and spores' treatments. The highest dry weight was recorded in spores' treatment followed by Rhizolex treatment (10 and 7 g/plant, respectively).Conclusions: results suggest that using chitinolytic Streptomyces strain 10d for the biological control of R. salani and damping-off disease of green bean plants can be an attractive alternative for pesticides in organic agriculture.

Characterization of Actinobacterial Strains as Potential Biocontrol Agents against Macrophomina phaseolina and Rhizoctonia solani, the Main Soil-Borne Pathogens of Phaseolus vulgaris in Cuba

“…(BCA-546 and CAI-8) significantly reduced charcoal rot in sorghum caused by M. phaseolina under semi-controlled conditions. On the other hand, our results are also in correspondence with those reported by Korayem et al [33] who evaluated the biological activity of S. parvulus strain 10d against R. solani on green beans in a semi-controlled trial with sterilized and non-sterilized soil. These authors showed that seedlings plants treated with a spore suspension of S. parvulus strain 10d showed the highest survival rate (88%) and the lowest DSroot (28%) in the whole of the experiment, showing much better results than those observed for seedlings treated with specific chemicals such as Rhizolex ® [31].…”

Efficacy of several chemical fungicides and biofungicides for controlling damping-off and root rot diseases in common bean under field conditions.

“…Various methods were reported to control damping-off and root rot diseases in common bean. These methods including cultivate resistant varieties (Brisa et al, 2007 andObala et al, 2012), cultural practices (Abeysinghe, 2007;Abawi andWidmer, 2000 andToledo-Souza et al, 2012), plant extracts Tripathi, 1991 andSoliman et al, 2013), biological control agents (Sallam, Nashwa et al, 2008;Mahamune and Kakde 2011;El-Fiki et al, 2014;Riad et al, 2015;Hussein et al, 2018 andKorayem et al, 2020) and the most effective method is chemical control (Theer, 2012;Buts and Singh, 2014;Elshahawy et al, 2016;Kumar et al, 2019 andKorayem et al, 2020 ).…”