Numerical and Species Composition of Insects Transmitting Viral Infection in North Ossetia

One of the major tasks in the production of original and elite potato seeds is to prevent the rapid re-infection of the healthy material with viruses in the open field. The high rate of infection with each subsequent reproduction reduces seed productivity and worsens the tuber varietal quality. Currently, about two dozen viruses that infect potatoes have been identified. In the field, most of the harmful viruses of potatoes are transmitted by insects such as aphids, cicadas and bedbugs. The purpose of our research was to study the species composition of transmitters and the intensity of their flight in North Ossetia. Studying the activity of the winged aphid vector is a prerequisite for the implementation of protective measures against re-infection of the sanitized material with viruses. The most important criteria characterizing aphids in transferring potato viruses during the growing season were as follows: the species composition, the dynamics of the potato planting periods, the timing of the critical threshold with regards to the number of aphids, and the total vector intensity during the growing season. There are very few aphid vectors in the mountain zone of the Republic of North Ossetia, which is at and above an altitude of 1,650 meters above sea level. Therefore, mountain regions of this height are a natural insulator against viral infection. In the foothill zone, the most numerous aphid vectors are bean, buckthorn, and alder buckthorn-willowherb aphids, whose number varies from 35 to 280 individuals per year on a Merike trap. Keywords: potatoes, insect vectors, a Merike trap, mountain zone, spatial isolatio

Multi-wavelength, all-solid-state, continuous wave mode locked picosecond Raman laser

We demonstrate the operation of a cascaded continuous wave (CW) mode-locked Raman oscillator. The output pulses were compressed from 28 ps at 532 nm down to 6.5 ps at 559 nm (first Stokes) and 5.5 ps at 589 nm (second Stokes). The maximum output was 2.5 W at 559 nm and 1.4 W at 589 nm with slope efficiencies up to 52%. This technique allows simple and efficient generation of short-pulse radiation to the cascaded Stokes wavelengths, extending the mode-locked operation of Raman lasers to a wider range of visible wavelengths between 500 - 650 nm based on standard inexpensive picosecond Nd:YAG oscillators

External cavity diamond Raman laser at 2.52 μm

An external-cavity diamond Raman laser at 2.52 μm, pumped by a home-built Tm:YLF laser, is reported. The maximum output pulse energy is 1.1 mJ for 4.74 mJ incidence yielding a total conversion efficiency of 23%.The slope efficiency is 49% and the Raman pulse duration is between 23-26 ns for 42 ns pump pulse duration

Fertility of Leached Chernozem and Productivity of Winter Wheat Depending on Fertilizers in a Forest-steppe Zone

The study revealed optimum doses, NPK combinations, terms and methods of fertilizer application, which provides for highly efficient use of nutrients thus maintaining the fertility of soils, high efficiency and high quality of winter wheat grains. The application of some mineral fertilizers was followed by some decrease (trend) of humus content in relation to control samples. The option manure+NPK was characterized by relative stabilization of humus condition of soil, and concerning the average humus content this option exceeded the control one by 0.32 %. Fertilizers clearly improved the nutrient status of leached chernozem under winter wheat enriching its 0–40 cm layer with mobile nitrogen (NН4+ and NO3−), phosphorus and potassium respectively by 6.0–9.2; 3.2–9.4; 9.3–36.7 and 21.5–32.8 mg/kg of soil on average per vegetation. Options with high doses of mineral fertilizers were characterized by the largest content. The application of fertilizers under winter wheat in N50−150P40−120K40−120 doses increased grain yield from 0.22 to 2.32 t/ha (6.9–72.5 %). The estimated option was the best

Phytoinsecticides to Fight Against Colorado Beetle

Nowadays researchers are focused on biological farming. In modern environmental conditions the reduction of the chemical load on the environment is a current issue. In the article the following plants are used as pest management, especially, with Colorado potato beetle: jimson weed, white hellebore, Camelina. They contain a lot of alkaloids and essential oils that inhibit weeds and frightening off potato pests. The use of such agricultural practices on large areas reduces the cost of chemical means of pest control and improves product quality while maintaining the environment

Passively Q-switched diode-pumped Cr4+:YAG/Nd3+:GdVO4 monolithic microchip laser

the realization of high repetition rate passively Q-switched monolithic microlaser is a challenge since a decade. To achieve this goal, we report here on the first passively Q-switched diode-pumped microchip laser based on the association of a Nd:GdVO4 crystal and a Cr4+:YAG saturable absorber. The monolithic design consists of 1 mm long 1% doped Nd:GdVO4 optically contacted on a 0.4 mm long Cr4+:YAG leading to a plano-plano cavity. A repetition rate as high as 85 kHz is achieved. The average output power is approximately 400 mW for 2.2 W of absorbed pump power and the pulse length is 1.1 ns