Potato infection with viruses in the Republic of Bashkortostan and ribonuclease activity in tubers

The paper presents the results of enzyme immunoassay (ELISA) of the presence of potato viruses S (PVS), M (PVM), Y (PVY), X (PVX), and Potato Leaf Roll Virus (PLRV) in tubers of various potato varieties grown in 2019 in the Republic of Bashkortostan. PVS, PVM, PVY, PVX were detected, the VSLK virus was not detected. The greatest infection with PVS, PVM, and PVX was observed in samples of tubers of early-maturing varieties. Tubers of mid-early and late-maturing varieties were more often affected by PVY than early-maturing ones, and PVX was not detected in plants of those varieties. Ribonuclease (RNase) activity in potato tubers of 14 varieties depended on the earliness of the variety, regardless of the soil and climatic conditions. A statistically significant positive correlation (P<0.05) was found between the abundance of PVS and PVM viruses and RNase activity in tubers of medium-early and late-maturing varieties, whereas, on the contrary, a negative correlation between PVM and RNase activity was revealed when analyzing tubers of early-maturing varieties. It is concluded that the prevalence of potato viruses in the territory of the Republic of Bashkortostan and the activity of RNase in tuber seedlings depend on the potato variety and the type of viruses.

Protection of spring wheat with biopreparations and fungicides in the forest steppe of Priobye: I. First results in extreme weather conditions

The paper presents data on a comparative test of the efficacy of chemical, fungal and bacterial fungicides in limiting the harmfulness of main diseases of spring wheat. The research was carried out on leached chernozem of the forest-steppe of Priobye of the Novosibirsk region. It was shown that Sternifag, SP reduces the development of root rot at the end of the growing season by 48 %, which is comparable to the effect of a chemical dressing agent Scarlet, ME (imazalil+tebuconazole) and is slightly inferior to the action of combined application of fungal preparation Trichocin, SP with the bacterial preparation Vitaplan, SP (55 %). Preplanting seed treatment effectively reduced the development of leaf infections: Scarlet, ME suppressed the development of Septoria blotch by 54 %, Scarlet, ME + Vitaplan, SP – of powdery mildew by 69 %, Trichotsin,SP + Vitaplan, SP – of brown rust by 74 %. Fungicide Titul 390, KKR reduced the development of these diseases by 60, 81 and 85 %, respectively. Alirin-B, W with Trichocin, SP suppressed brown rust by 64 %. Cellulolytic activity increased 1.3–1.9 times compared to the control as a result of the action of biological products and Sternifag, SP. The amount of plant residues decreased 2.4 and 1.9 times 15 and 30 days after application. The greatest increase in yield was provided by chemical fungicides – 0.7 t / ha, they were not inferior to the use of Alirin-B, W with Vitaplan, SP against the background of etching with Scarlet, ME fungicide.

Characterization of Zymoseptoria tritici populations in Belarus by morphologic and cultural features

Septoria leaf blotch caused by Zymoseptoria tritici is one of the most harmful diseases in Belarus. Isolates of the pathogen were obtained from northern, central and southern populations: in 2018–2019, whichvaried significantly among in the structure of colonies. The rate of fungal isolates forming yeast-like colonies decreased from 55.0 % in the North of Belarus to 6.7 % in the South, whereas incidence of filamentous isolates increased from 31.3 % to 80.0 %, respectively. In the northern population, phenotypic diversity was high, while in the southern population it was the lowest (Shannon’s index was 1.53 and 1.14, respectively).

Introduction to Molecular Diagnostics of Insects

Insects play an important role in biocenoses due to their abundance and wide (cosmopolitan) distribution. Many insects are crop pests. An effective pest control could be realized in case of proper species identification, which is usually managed by morphological analysis. Molecular methods allow to deep study of many issues of insect biology. In particular, traditional approach can not ordinary identify a species at all stages of their life cycle, whereas molecular methods can it. This review covers a wide range of issues related to the molecular genetic analysis of insects. In the first section we consider the methods of fixation and storage of insect specimens, as well as their impact on DNA quality. Further, we provide general information on population study design. Various schemes of DNA extraction, examples of both express techniques and more thorough protocols for DNA extraction and their purification are provided. In addition, methods of DNA isolation that allow to preserve a specimen integrity for further morphological studies are considered. The methods of DNA quality control are described in detail, that is important for PCR analysis. The last section provides various methods of PCR analysis, that we exemplify by studies aimed to elucidate both fundamental issues and practical problems.

The first detection of Botryosphaeria sinensis on white lupine

Fungal strain MF KP-12.1, which is similar in morphological and cultural characteristics to Botryosphaeria fungi, was isolated from the seeds of white lupine variety Dega grown in Oryol region in 2018. Phylogenetic analysis of the large rRNA subunit (LSU), elongation factor-1α (TEF) and internal transcribed spacer (ITS) fragments was used to accurately identify the isolated strain as B. sinensis. When 2-week-old white lupine plants were treated under laboratory conditions with mycelial suspension of B. sinensis MF KP-12.1, plant damage reached 67 % on day 3, and 100 % plant death was observed on day 10. Pathogenicity of B. sinensis MF KP-12.1 was confirmed by re-isolation of the strain from damaged plant tissue. This is the first detection of B. sinensis on white lupine, which has not been previously reported as a host for this fungus. It is also the first detection of B. sinensis in Russia.

Variability of infestation of rose varieties by the spider mite Tetranychus urticae under conditions of application of Phytoseiulus persimilis or acaricides

The two-spotted spider mite Tetranychus urticae is a dangerous polyphagous pest of agricultural and ornamental plants. In a commercial greenhouse treated with acaricides or biological control using predatory mite Phytoseiulus persimilis individual varieties of roses differed significantly in terms of the average annual infestation by the pest mite. On the poorly populated rose varieties, the biological control agent application was more effective as compared to the acaricides. To effectively control the pest, the required predatory mite rates were 4.6–8.7 times higher on varieties with a minimal spider mite infestation (Aqua and Deep Water) as compared to the maximal pest infestation (Heaven and Brazil).

Compatibility of the fungus Lecanicillium muscarium and the predatory mite Amblyseius swirskii for their combined application against the greenhouse whitefly Trialeurodes vaporariorum

The present study evaluated effects of the fungus Lecanicillium muscarium (Ascomycota: Hypocreales) and an organic extract from its mycelium on the greenhouse whitefly Trialeurodes vaporariorum (Hemiptera: Aleyrodidae) and its predator, mite Amblyseius swirskii (Acari: Phytoseiidae). Mites were exposed to fungal spores or organic extract prepared from L. muscarium mycelium. No negative effect was shown on the predator feeding on T. vaporariorum nymphs treated with fungal conidia at a concentration of 5 × 107 spores/ml; by day six the number of mite eggs and nymphs was 18.7 % higher than on leaves treated with Tween 80. In contrast, treatment of leaves with a 0.5 % alcohol extract derived from L. muscarium mycelium caused 35 % mortality of A. swirskii adults by day two. In a trial conducted in a commercial greenhouse on rose plants, the application of L. muscarium conidia followed by the release of A. swirskii suppressed T. vaporariorum more effectively than each of the control agents applied separately.

Contamination of grain in West Siberia by Alternaria fungi and their mycotoxins

The ubiquitous occurrence of Alternaria fungi belonging to sections Alternaria and Infectoriae was confirmed using real-time PCR in wheat, barley and oat grain grown in West Siberia in 2018‒2019. The DNA amount of Alternaria section Alternaria fungi varied from 53×10-4 to 21731×10-4 pg/ng and on average exceeded the DNA amount of Alternaria section Infectoriae fungi by 4.5‒14.6 times, depending on the crop and harvest year.The average DNA amount of Alternaria fungi belonging to both sections in the oat grain was lower than in wheat and barley grain. The grain samples from Altay region were the most infected with Alternaria fungi. The alternariol (AOH), alternariol monomethyl ether (AME), tentoxin (TEN), and tenuazonic acid (TeA) mycotoxins produced by Alternaria fungi were detected by HPLC-MS/MS in 23 %, 6 %, 85 %, and 83 % of analyzed grain samples, respectively. The majority (61 %) of the samples contained two Alternaria mycotoxins in the grain (mainly TEN and TeA), 19 % of the samples three mycotoxins, and only one sample all four together. In the most of samples the content of Alternaria mycotoxins did not exceed 100 μg/kg, and only TeA content was higher (from 113 to 14963 μg/kg) than others. The significant differences in grain crops by the Alternaria mycotoxins content were revealed: more amounts of AOH, AME, and less amount of TEN were found in oat grain then in barley grain. A high positive significant correlation between the DNA amount of Alternaria section Alternaria fungi and TeA was established that indicates the role of these fungi as the main producers of TeA in the grain.

Modern groups of insecticides: diamides and meta-diamides

The review summarizes and analyzes the data of foreign authors on the practical efficacy, mechanisms of action and insect resistance concerning insecticides of the groups of diamides and meta-diamides. The prospects of their application in Russia in agriculture and medical disinsection are considered. Insects resistant to OР’s, carbamates, pyrethroids remain the susceptibility to diamides and meta-diamides. Broflanilide, a pro-insecticide, which, due to its transformation into desmethylbroflanilide in the body of arthropods, acquires physicochemical properties leading to improved lipophilicity, water solubility, stability, affecting systemic activity, slowing down the action on harmful insects and increased selectivity for non-target species, is considered in detail. In several countries of the world where diamides are widely used in the controlling agricultural pests, a high resistance of several species of noctuids, diamondback moth, pyralid moths, tomato leafminer, etc. has been established. The key factors that determined the resistance to diamide in Thailand were the lack of insecticide rotation, minimal crop rotation, insufficient insecticide dosage, and irrigation. The necessity of introducing diamides and meta-diamides into the insecticide rotation schemes in order to control the insects resistant to traditionally used active substances was revealed.

Does arbuscular mycorrhiza favor invasion of some Asteraceae tribes?

Invasive species, including more than three dozen Asteraceae, such as Solidago canadensis, Leucanthemum vulgare, Senecio inaequidens etc, pose serious threat to ecosystem health. Arbuscular mycorrhizal symbiosis is a key factor for distribution of invasive species of some Asteraceae tribes, including Astereae, Anthemideae, Senecioneae, Gnaphalieae, Cardueae, and Cichorieae. The formation of invasion-friendly plant communities has occurred through increasing nutrient and water availability, hormonal regulation, production of bioactive compounds, and mycorrhiza-induced resistance of host plants. Native species are displaced through the influence on soil microbiota, mycorrhizal and nutrient status of neighboring plants, and several other parameters. Allelopathic influences and symbiotic interactions with bacteria and other fungi can inhibit these processes. Understanding the mycorrhizal status of invasive weeds, in our opinion, is a necessary condition for their successful control.