Seasonal dynamics of three lepidopteran stored grain pests in Slovenia

In the period 2004-2006 seasonal dynamics of Mediterranean flour moth (Ephestia kuehniella), Indianmeal moth (Plodia interpunctella) and Angoumois grain moth (Sitotroga cerealella) was studied in the mills and grain warehouses in central Slovenia. For this purpose pheromone traps were used from April until December, and the males of all three lepidopteran pests were counted in two week intervals. The three insect pests under investigation developed two peaks in capture per year that might represent two distinct generations per year. In the maize open air storage Ephestia kuehniella was the most numerous, while Plodia interpunctella was more frequent in the closed storage in mills and warehouses, Sitotroga cerealella was slightly less common in these latter closed warehouses. Keywords: Monitoring, Lepidoptera, Stored grain pest, Pheromones, Sloveni

Development of high-throughput methods to screen disease caused by Rhizoctonia solani AG 2-1 in oilseed rape

Background: Rhizoctonia solani (Kühn) is a soil-borne, necrotrophic fungus causing damping off, root rot and stem canker in many cultivated plants worldwide. Oilseed rape (OSR, Brassica napus) is the primary host for anastomosis group (AG) 2-1 of R. solani causing pre- and post-emergence damping-off resulting in death of seedlings and impaired crop establishment. Presently, there are no known resistant OSR genotypes and the main methods for disease control are fungicide seed treatments and cultural practices. The identification of sources of resistance for crop breeding is essential for sustainable management of the disease. However, a high-throughput, reliable screening method for resistance traits is required. The aim of this work was to develop a low cost, rapid screening method for disease phenotyping and identification of resistance traits. Results: Four growth systems were developed and tested: (1) nutrient media plates, (2) compost trays, (3) light expanded clay aggregate (LECA) trays, and (4) a hydroponic pouch and wick system. Seedlings were inoculated with virulent AG 2-1 to cause damping-off disease and grown for a period of 4–10 days. Visual disease assessments were carried out or disease was estimated through image analysis using ImageJ. Conclusion: Inoculation of LECA was the most suitable method for phenotyping disease caused by R. solani AG 2-1 as it enabled the detection of differences in disease severity among OSR genotypes within a short time period whilst allowing measurements to be conducted on whole plants. This system is expected to facilitate identification of resistant germplasm

Mitochondrial ROS regulate thermogenic energy expenditure and sulfenylation of UCP1

Brown adipose tissue (BAT) can dissipate chemical energy as heat through thermogenic respiration, which requires uncoupling protein 1 (UCP1)1,2. Thermogenesis from BAT and beige adipose can combat obesity and diabetes3, encouraging investigation of factors that control UCP1-dependent respiration in vivo. Herein we show that acutely activated BAT thermogenesis is defined by a substantial increase in mitochondrial reactive oxygen species (ROS) levels. Remarkably, this process supports in vivo BAT thermogenesis, as pharmacological depletion of mitochondrial ROS results in hypothermia upon cold exposure, and inhibits UCP1-dependent increases in whole body energy expenditure. We further establish that thermogenic ROS alter BAT cysteine thiol redox status to drive increased respiration, and Cys253 of UCP1 is a key target. UCP1 Cys253 is sulfenylated during thermogenesis, while mutation of this site desensitizes the purine nucleotide inhibited state of the carrier to adrenergic activation and uncoupling. These studies identify BAT mitochondrial ROS induction as a mechanism that drives UCP1-dependent thermogenesis and whole body energy expenditure, which opens the way to develop improved therapeutic strategies for combating metabolic disorders

Characterizing the scent and chemical composition of Panthera leo marking fluid using solid-phase microextraction and multidimensional gas chromatography–mass spectrometry-olfactometry

Lions (Panthera leo) use chemical signaling to indicate health, reproductive status, and territorial ownership. To date, no study has reported on both scent and composition of marking fluid (MF) from P. leo. The objectives of this study were to: 1) develop a novel method for simultaneous chemical and scent identification of lion MF in its totality (urine + MF), 2) identify characteristic odorants responsible for the overall scent of MF as perceived by human panelists, and 3) compare the existing library of known odorous compounds characterized as eliciting behaviors in animals in order to understand potential functionality in lion behavior. Solid-phase microextraction and simultaneous chemical-sensory analyses with multidimensional gas-chromatography-mass spectrometry-olfactometry improved separating, isolating, and identifying mixed (MF, urine) compounds versus solvent-based extraction and chemical analyses. 2,5-Dimethylpyrazine, 4-methylphenol, and 3-methylcyclopentanone were isolated and identified as the compounds responsible for the characteristic odor of lion MF. Twenty-eight volatile organic compounds (VOCs) emitted from MF were identified, adding a new list of compounds previously unidentified in lion urine. New chemicals were identified in nine compound groups: ketones, aldehydes, amines, alcohols, aromatics, sulfur-containing compounds, phenyls, phenols, and volatile fatty acids. Twenty-three VOCs are known semiochemicals that are implicated in attraction, reproduction, and alarm-signaling behaviors in other species

Root-emitted volatile organic compounds: can they mediate belowground plant-plant interactions?

peer reviewedBackground Aboveground, plants release volatile organic compounds (VOCs) that act as chemical signals between neighbouring plants. It is now well documented that VOCs emitted by the roots in the plant rhizosphere also play important ecological roles in the soil ecosystem, notably in plant defence because they are involved in interactions between plants, phytophagous pests and organisms of the third trophic level. The roles played by root-emitted VOCs in between- and within-plant signalling, however, are still poorly documented in the scientific literature. Scope Given that (1) plants release volatile cues mediating plant-plant interactions aboveground, (2) roots can detect the chemical signals originating from their neighbours, and (3) roots release VOCs involved in biotic interactions belowground, the aim of this paper is to discuss the roles of VOCs in between- and within-plant signalling belowground. We also highlight the technical challenges associated with the analysis of root-emitted VOCs and the design of experiments targeting volatile-mediated root-root interactions. Conclusions We conclude that root-root interactions mediated by volatile cues deserve more research attention and that both the analytical tools and methods developed to study the ecological roles played by VOCs in interplant signalling aboveground can be adapted to focus on the roles played by root-emitted VOCs in between- and within-plant signalling

Efectividad de las vallas electrificadas con electrodos de cobre en el control de las babosas (Arion spp.) bajo corriente continua y voltaje eléctrico

Terrestrial slugs of the genus Arion are native to Europe, where they represent an important agricultural pest. This study determined the effectiveness of electrified fencing on barrier crossing by slugs. The fences were placed in glass insectariums. DC (direct current) voltages (2, 4, 6, 8 and 10 V) applied across the fence were tested together with limiting electric current values (0.1, 0.01 and 0.001 mA). Four categories of behavior were identified for slugs in the presence of an electrified fence: the animals (1) were stationary, (2) were moving but avoided the electrodes, (3) touched the electrodes and/or attempted unsuccessfully to cross the electrified fence and (4) succeeded in crossing the electrified fence. The effect of the applied voltages and the limiting current values on slug movement was highly significant. Forty-one percent of slugs crossed the fence at the lowest applied voltage, whereas only 1% of slugs succeeded in crossing at the highest voltage. The lowest limiting current values resulted in the most frequent fence crossings. For larger voltages and limiting currents, the frequency of slug crossings was effectively zero at fence regions positioned on the glass walls of the insectariums. In conclusion, this method of slug prevention may be highly effective, environmentally friendly and may result in deterrence, not death, of terrestrial slugs, a ubiquitous pest responsible for significant economic damage in agriculture.Las babosas terrestres del género Arion son nativas de Europa, donde representan una importante plaga agrícola. En este trabajo se determinó la eficacia de usar barreras electrificadas para impedir el paso de las babosas. Se colocaron vallas electrificadas en insectarios de vidrio y se aplicaron voltajes de CC (2, 4, 6, 8 y 10 V), limitados por diferentes valores de corriente eléctrica (0,1, 0,01 y 0,001 mA). Se identificaron cuatro diferentes respuestas de comportamiento de las babosas: (1) se quedaron quietas, (2) se movieron evitando los electrodos, (3) tocaron los electrodos e/o intentaron, sin éxito, cruzar la valla y (4) lograron cruzar la valla electrificada. El efecto de los voltajes aplicados y de los valores de corriente limitantes en el movimiento de las babosas fue muy significativo. El 41% de las babosas cruzó la valla con el menor voltaje aplicado, mientras que sólo el 1% de las babosas logró cruzar con el voltaje más alto. Los valores más bajos de corriente dieron lugar a los cruces más intensos de la valla. Para tensiones y corrientes más altas la frecuencia de los cruces de las babosas fue prácticamente cero en las zonas de la valla colocada en las paredes de vidrio de la insectarios. En conclusión, este método de control de las babosas puede ser muy eficaz, respetuoso con el medio ambiente y producir disuasión, no la muerte, de las babosas terrestres, una plaga responsable de importantes pérdidas económicas en la agricultura

The effectiveness of electrified fencing using copper electrodes for slug (Airon spp.) control with direct electric current and voltage

Terrestrial slugs of the genus Arion are native to Europe, where they represent an important agricultural pest. This study determined the effectiveness of electrified fencing on barrier crossing by slugs. The fences were placed in glass insectariums. DC (direct current) voltages (2, 4, 6, 8 and 10 V) applied across the fence were tested together with limiting electric current values (0.1, 0.01 and 0.001 mA). Four categories of behavior were identified for slugs in the presence of an electrified fence: the animals (1) were stationary, (2) were moving but avoided the electrodes, (3) touched the electrodes and/or attempted unsuccessfully to cross the electrified fence and (4) succeeded in crossing the electrified fence. The effect of the applied voltages and the limiting current values on slug movement was highly significant. Forty-one percent of slugs crossed the fence at the lowest applied voltage, whereas only 1% of slugs succeeded in crossing at the highest voltage. The lowest limiting current values resulted in the most frequent fence crossings. For larger voltages and limiting currents, the frequency of slug crossings was effectively zero at fence regions positioned on the glass walls of the insectariums. In conclusion, this method of slug prevention may be highly effective, environmentally friendly and may result in deterrence, not death, of terrestrial slugs, a ubiquitous pest responsible for significant economic damage in agriculture