Evaluation of indigenous Trichoderma isolates from Manipur as biocontrol agent against Pythium aphanidermatum on common beans

Pythium aphanidermatum is one of the common causal pathogen of damping-off disease of beans (Phaseolus vulgaris L.) grown in Manipur. A total of 110 indigenous Trichoderma isolates obtained from North east India were screened for their biocontrol activity which can inhibit the mycelial growth of P. aphanidermatum, the causal organism of damping-off in beans. Out of the total isolates, 32% of them showed strong antagonistic activity against P. aphanidermatum under in vitro condition and subsequently 20 best isolates were selected based on their mycelial inhibition capacity against P. aphanidermatum for further analysis. Different biocontrol mechanisms such as protease, chitinase, β-1,3-glucanase activity, cellulase and production of volatile and non-volatile compounds were also assayed. Based on their relative biocontrol potency, only three indigenous Trichoderma isolates (T73, T80 and T105) were selected for pot culture experiment against damping-off diseases in common beans. In greenhouse experiment, Trichoderma isolates T-105 significantly reduced the pre- and post-emergence damping-off disease incidence under artificial infection with P. aphanidermatum and showed highest disease control percentage

Numerical characterisation and experimental validation of Auslron top submerged multi-injection system

The present paper presents a numerical study of the fluid flow structure inside an elliptical liquid bath, agitated by a top submerged gas injection system. Using the Eulerian-Eulerian approach, a three-dimension gas-liquid transient numerical model coupled with the standard k-ε model is developed. Various combinations of operating parameters are investigated and the numerical predictions are validated against the laser doppler anemometer (LDA) experimental data. The results indicate that at a higher gas flowrate a better mixing at the bottom of the bath is achieved. On the effect of the lance submergence a deeper submergence level gives highly improved agitation and mixing within the bath. The comparisons of the numerical predictions with experimental data under various operating conditions show a reasonable agreement for both mean velocity and turbulent fluid flow characteristics. Furthermore, the development of a new empirical correlation based on Froude number is presented