Exploitation of trichoderma species on the growth of Pythium Aphanidermatum in Chilli

Damping-off of chilli caused by Pythium aphanidermatum is a major nursery disease in vegetables. In vitro experiments evaluated the effect of eight isolates of Trichoderma species (from chilli rhizosphere) were tested against P. aphanidermatum. All the Trichoderma species had varied antagonistic effects against the pathogen. Among them, TVC3 recorded maximum growth inhibition of P. aphanidermatum and produced more amounts of volatile and non-volatile metabolites. The culture filtrate of the Trichoderma isolate TVC3 recorded complete inhibition on the mycelial growth of pathogen at 15 percent concentration. Moreover, chilli seeds treated with culture filtrate of the isolate TVC3 recorded maximum germination percentage, shoot length, root length and vigour index of chilli. The study identified the Trichoderma isolate (TVC3) performed well in inhibiting the mycelial growth of pathogen as well as increased the plant growth in chilli.

Evaluation of soil microorganisms with inhibitory activity against rhizoctonia solani causal agent of the damping-off of canola

Pre-and post-emergence damping-off of canola seedlings caused by Rhizoctonia solani is a serious disease in Western Canada. Other fungi such as Fusarium spp. and Pythium spp. are also related to seedling damping-off. To-day, the search of soil bacteria is becoming a tool to use microorganisms as potential biocontrol agents for several plant diseases. The purpose of this research was to detect bacteria to biologically control R. solani, Pyrhium spp., and Fusarium spp. Soil samples were collected throughout Alberta during 1987 to isolate bacteria. Canola seedlings were also used to obtain bacteria from the same samples. Plant pathogenic fungi were tested to detect the antagonistic activity of the isolates. Tests were made with coated canola seeds, amendments and fresh of freeze-dried cells. Three hundred forty-one bacterial cultures were isolated. Only 16 inhibited fungal growth: 7 showed the same effects against R. solani and 9 showed uneven effects. Some isolates showed a weak action to Pythium spp. and Fusarium spp. three isolated showed inhibitory effect on R. solani and Pythium spp. isolate F1 improved by about 50% the germination of canola seeds in inoculated pots when compared with the inoculated control. Coated seeds had low germination and emergence was below the inoculated control. the emergence of vanola seedlings was very much improved when isolate 147 was delivered as an amendment in inoculated pots. Identification showed that 3 bacterial belonged to Bacillus spp., 4 to green fluorescent Pseudomonas spp. and 2 were Streptomyces spp