Rhizoctonia solani and Sclerotium rolfsii are fungal pathogens responsible for severe crown and stem rot of horticultural crops worldwide. Chemical control of these pathogens involves technical, environmental and toxicological risks. To find eco-compatible and safer alternative control methods, the effectiveness of the newly selected bacterial isolates Burkholderia cepacia (T1A-2B) and Pseudomonas spp. (T4B-2A), originating from suppressive organic matrices, were tested on tomato plants grown under both controlled and field conditions. The potential antagonists were compared with two commercial biofungicides (Bacillus subtilis BSF4® and Trichoderma asperellum TV1®) and four synthetic fungicides (Tolclofos-methyl, Azoxystrobin, Fosetyl-Al and Fosetyl-Al + Propamocarb). In the rhizosphere of tomato plants treated by both antagonists, the total bacterial population was about 100-fold higher than that recovered from untreated control. Scanning electron microscope observations revealed that both biocontrol bacteria efficiently colonized the root surface and were capable of adhering to tomato roots by producing biofilm-like structures. In a 2-year field experiments, the novel selected biocontrol bacteria significantly reduced both incidence and severity of disease caused by the pathogens to tomato. The effectiveness of the antagonists was equal to that of T. asperellum(TV1), better than that of B. subtilis (BSF4) and was also comparable to that of synthetic fungicides. The results of these investigation encourages further studies aimed at optimizing the novel biocontrol bacteria for application in controlling crown and root rot of horticultural crops.
Activity of antagonist bacteria for the biological control of Rhizoctonia solani and Sclerotium rolfsii on tomato
DE CURTIS, Filippo;LIMA, Giuseppe;
2009-01-01
Abstract
Rhizoctonia solani and Sclerotium rolfsii are fungal pathogens responsible for severe crown and stem rot of horticultural crops worldwide. Chemical control of these pathogens involves technical, environmental and toxicological risks. To find eco-compatible and safer alternative control methods, the effectiveness of the newly selected bacterial isolates Burkholderia cepacia (T1A-2B) and Pseudomonas spp. (T4B-2A), originating from suppressive organic matrices, were tested on tomato plants grown under both controlled and field conditions. The potential antagonists were compared with two commercial biofungicides (Bacillus subtilis BSF4® and Trichoderma asperellum TV1®) and four synthetic fungicides (Tolclofos-methyl, Azoxystrobin, Fosetyl-Al and Fosetyl-Al + Propamocarb). In the rhizosphere of tomato plants treated by both antagonists, the total bacterial population was about 100-fold higher than that recovered from untreated control. Scanning electron microscope observations revealed that both biocontrol bacteria efficiently colonized the root surface and were capable of adhering to tomato roots by producing biofilm-like structures. In a 2-year field experiments, the novel selected biocontrol bacteria significantly reduced both incidence and severity of disease caused by the pathogens to tomato. The effectiveness of the antagonists was equal to that of T. asperellum(TV1), better than that of B. subtilis (BSF4) and was also comparable to that of synthetic fungicides. The results of these investigation encourages further studies aimed at optimizing the novel biocontrol bacteria for application in controlling crown and root rot of horticultural crops.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
