Use of cultivar resistance and crop rotation with Bacillus subtilis for clubroot control in canola

Non-Peer ReviewedThis study was conducted to assess additional strategies potentially complimentary to cultivar resistance or biocontrol in control of clubroot. New granular Bacillus subtilis formulations and a seed dressing method were developed to facilitate biofungicide delivery in field trials. The granular formulations were applied in furrow during seeding at 50 kg/ha to a clubroot resistant (CR) and susceptible (CS) canola cultivar, respectively, in three field trials. The seed dressing applied approximately 1×105 to 5×106 cfu/seed doses of the biocontrol agent, and was evaluated on the CS cultivar seeded to different crop-rotation scenarios where the plots had a 1-year, 3-year, or 11-year break from last canola crop. Clubroot disease pressure was high at all trial sites with disease severity indexes (DSI) ranging from 69% to 98% on the CS cultivar. None of the granular formulations reduced clubroot substantially, whereas the CR cultivar showed a high effect, reducing DSI to below 15% and doubling the yield over that of CS cultivar. Plots of varying rotation showed a pattern of clubroot pathogen pressure, with those of 1-year break from canola being the highest. The DSI for all rotational scenarios was high, reaching 100% in short-rotation plots. Biofungicide seed dressing did not reduce DSI, but longer crop rotation often reduced gall size slightly, showed much milder above-ground damage, and increased the yield significantly relative to short rotation in two separate trials. Even a 3-year break from canola was highly beneficial, with the yield doubled as opposed to that with only 1-year break from canola

Generation of high-energy-density ion bunches by ultraintense laser-cone-target interaction

A scheme in which carbon ion bunches are accelerated to a high energy and density by a laser pulse (similar to 10(21) W/cm(2)) irradiating cone targets is proposed and investigated using particle-in-cell simulations. The laser pulse is focused by the cone and drives forward an ultrathin foil located at the cone's tip. In the course of the work, best results were obtained employing target configurations combining a low-Z cone with a multispecies foil transversely shaped to match the laser intensity profile. (C) 2014 AIP Publishing LLC

Generation of hemispherical fast electron waves in the presence of preplasma in ultraintense laser-matter interaction

AbstractHemispherical electron plasma waves generated from ultraintense laser interacting with a solid target having a subcritical preplasma is studied using particle-in-cell simulation. As the laser pulse propagates inside the preplasma, it becomes self-focused due to the response of the plasma electrons to the ponderomotive force. The electrons are mainly heated via betatron resonance absorption and their thermal energy can become higher than the ponderomotive energy. The hot electrons easily penetrate through the thin solid target and appear behind it as periodic hemispherical shell-like layers separated by the laser wavelength.</jats:p