Weed potential of Mikania micrantha H.B.K., and its control in fallows after shifting agriculture (Jhum) in North-East India

Mikania micrantha H.B.K. is an exotic, perennial weed which colonizes communities developing after slash and burn agriculture (Jhum) at lower elevations of north-east India. The population dynamics and reproductive potential of M. micrantha was studied. Reproduction through ramets arising from rosettes exceeded that from seeds. The ramet population growth was highest during the monsoon season as a consequence of high population birth and large-scale mortality. Net population increased with increasing age of the fallow for 3 years, and declined drastically in 6- and 12-year-old fallows. Biomass was allocated mainly to the ramet root system in younger fallows and to the rosette root system in older fallows. Seed reproduction potential peaked in a 3-year-old fallow and declined rapidly thereafter. The significance of the results in terms of natural elimination of the species through succession, and the increased weed potential leading to arrested succession under short jhum cycles is discussed

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Not AvailableTobacco (Nicotiana tobaccum L.) is the world’s third most important commercial crop, after sugarcane (Saccharum officinarum) and cotton (Gossypium hirsutum). Wilt is one of the major diseases of tobacco and at national level the yield losses encountered due to Fusarium wilt was reported to the tune of 60 per cent. Fusarium wilt on tobacco was identified in Karnataka during 2000. Since then it has become a threat to tobacco cultivation. There were sporadic incidence of Fusarium reported in Northern Light Soils (NLS) so to find out the incidence levels Random field survey for Fusarium wilt disease in NLS region of Andhra Pradesh was conducted, survey revealed varying degrees of disease incidence during 2015-2017. Wilt incidence was recorded more in Koyalagudem with 29.17 and 36.36% during 2016 and 2017 respectively (Fig. 2). Tobacco fields showed wilt with severity in the range of 12.5 - 30%, 8.33 - 29.17% and 14.17 - 36.36% during 2015-2017 respectivelyNot Availabl

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Not AvailableThe microbial free extracts of the Neem based formulations – Wellgro samples (autoclaving and membrane filtration) were tested against the five antagonistic fungal microorganisms (Trichoderma harzianum, T. hamatum, T. viride, and Trichoderma harzianum - 001 and T. viride - 002). Poison food technique was followed to test the effect of Wellgro crops and Wellgro soil at five different concentrations viz., 0.5, 1.0, 2.5, 5.0 and 10% on the growth of these microorganisms. At lower concentrations, Wellgro soil was found to have no effect on the growth of the test fungal spp. However, with increase in concentration above 2.5% there was significant reduction in the spore germination of the test fungi in-vitro. The study helps in fortification of beneficial microorganisms using Neem formulations (Wellgro) as medium for multiplication there by increasing the application and antagonistic efficiency by fitting in sustainable IPM programmes.Not Availabl

Evaluating delamination growth in composites under dynamic loading using infrared thermography

In this paper, a method has been developed to use thermography for the quantitative analysis of a delamination area under dynamic loading. To demonstrate this method, a coupon was developed with double shear configuration and an initial delamination consisting of a PTFE insert. The coupon was tested under fatigue loading and an infrared (IR) camera was used to monitor the thermal response and delamination growth of the coupon during loading. The data from the thermal camera was processed in 2 steps, firstly a fast Fourier transform (FFT) was used to transform the raw data from time domain to frequency domain. In the second step, FFT thermographs were further processed using an image segmentation algorithm. Here, the thermal plots are segmented to separate the delaminated and un-delaminated areas. By computing the number of pixels in the delaminated region, the area of delamination was obtained at each cycle and has been plotted against the cycles to failure. The strain energy was computed with the help of force and displacement data from the test machine. Such signals allowed computing the fatigue propagation curves and understanding the fatigue behaviour of the test samples. This method looks promising and can be extended to test samples that cannot be tested by conventional testing methodsStructural Integrity & Composite