Assessment of winter soft and durum wheat varieties for resistance to yellow and dark brown spots

Winter wheat varieties sown in the Rostov region are characterized by varying degrees of resistance to pests. The size and quality of the wheat harvest are threatened not only by weather conditions, but are reduced by various pathogens, among which yellow and dark brown spots have recently played a large role. Therefore, the aim of the research is to search for sources of resistance among varieties and samples of winter wheat to the causative agents of pyrenophora (Pyrenophora tritici-repentis) and dark brown spot (Cochliobolus sativus). Resistant varieties serve as an ideal factor inhibiting epiphytotics and improving the ecological environment in general. Disease monitoring was carried out in research and production teams of the Federal State Budgetary Scientific Institution Agrarian Research Center “Donskoy”. Laboratory research - in the laboratory of mycology and phytopathology of the All-Russian Institute for Plant Protection. The object of research is 226 varieties and samples of winter soft and durum wheat obtained from the department of selection of winter wheat of the Federal State Budgetary Scientific Institution of the ANC “Donskoy”. It was established: in laboratory conditions (VIZR), 15 varieties and samples showed high resistance to yellow spot in soft winter wheat of intensive type. In studies on resistance to dark brown spot out of 155 samples of winter soft wheat, no highly resistant ones were found.

First Report of Cercospora Leaf Spot Caused by Cercospora cf. flagellaris on Okra in China

Okra [Abelmoschus esculentus (L.) Moench], which belongs to the family Malvaceae, is widely grown in the tropics, sub-tropics and warmer areas of the temperate zones for its immature seed pods which are consumed as a vegetable. In China, okra pods are consumed as not only vegetables but also as a traditional medicine to cure dental diseases and gastric ulcers. During September 2018 to June 2019, extensive spots on okra leaves were observed in several commercial fields (approximately 2.0 hectares), with disease incidence of approximately 25%~50% in the Yanqing District (115°98′E, 40°46′N) of Beijing, China. Symptoms of the disease initially appeared as small pale brown spots with yellow haloes. As the disease progressed, some spots gradually coalesced, forming larger irregular dark brown lesions. The centers of the lesions became grayish white. A total of 13 small fragments (3 to 5 mm) excised from the lesion margins were sterilized in 1% sodium hypochlorite (NaClO) for 1 min, followed by three washes with sterile distilled water, and then placed on potato dextrose agar (PDA) and incubated at 25°C in the dark for 5 days. In total, 21 cultures were obtained and purified by single-spore subcultures on PDA for morphological identification. The colonies on PDA were whitish to gray, with cottony aerial mycelium. Conidiophores were fasciculate, olivaceous brown, straight or geniculate, uniform in width, multiseptate, and ranged from 286/span> to 711 μm (avg. = 578 μm, n = 50). Conidia were hyaline, slightly curved or straight, needle shaped, truncate at the base, and terminal at the tip, 3–17-septate, and measuring 52 to 231 μm (avg. = 182 μm, n = 50). The morphological features were consistent with Cercospora cf. flagellaris Ellis & G. Martin (Groenewald et al. 2013). Pathogenicity tests were conducted on potted okra plants cv. ‘Jiayuan’. Twenty four healthy okra plants at the true leaf stage were sprayed with conidial suspensions (1 × 106 conidia/mL), incubated at a glass cabinet maintained at 25°C and 90% relative humidity (RH). To each leaf approximately 10 mL of conidial suspension was applied. Plants sprayed with water were used as controls. Seven days later, dark brown spot, which were identical to those observed in the fields, were observed on inoculated leaves, whereas the control plants remained healthy. C. cf. flagellaris was reisolated from symptomatic leaves, confirming Koch’s Postulates. Genomic DNA was extracted from fungal mycelium using the Plant Genomic DNA Kit (Tiangen Biotech Co. Ltd., Beijing, China). The nuclear ribosomal internal transcribed spacer region (ITS), and portions of the actin (ACT), histone H3 (HIS3), and translation elongation factor 1-α (TEF1) genes were amplified using primers ITS1/ITS4 (Groenewald et al. 2013), ACT-512F/ACT-783R (Carbone & Kohn 1999), CYLH3F/CYLH3R (Crous et al. 2006), and EF1-728F/EF1-986R (Carbone & Kohn 1999). The resulting 542 bp ITS, 226 bp ACT, 410 bp HIS3 and 306 bp TEF1 sequences of isolate QK14091813 were deposited in GeneBank (Accession nos. MT949700, MT949701, MT949702 and MT949703, respectively). The ITS, ACT, HIS3 and TEF1 sequences shared 99.42% to 100% identities to previously published sequences of C. cf. flagellaris (Accession nos. MN633275 for ITS, MF680960 for ACT, MK991295 for HIS3, and MK991292.1 for TEF1, respectively). Multi-locus phylogenetic analyses (ITS, ACT, HIS3, and TEF1) were performed by neighbor-joining method using MEGA 7.0. The resulting trees showed that C. cf. flagellaris isolate QK14091813 (this study) nested within the clade that includes other isolates of C. cf. flagellaris with a 99% confidence level. To our knowledge, this is the first report of C. cf. flagellaris causing leaf spot on okra (Farr and Rossman 2020). The pathogen has a worldwide distribution and an unusually broad host range, which can be of great significance, and the plant protection policy of priority to prevention and synthetical prevention should be followed.

The effect of chitin on the biological activity of Bacillus subtilis strains

The aim of the work was to assess the effect of various forms of chitin and chitosan during submerged cultivation of Bacillus subtilis strains, which form the basis of the laboratory sample Vitaplan, CL, on the synthesis of chitinase, as well as on the antagonistic activity and inducing effect of B. subtilis strains in the pathosystems of wheat - Cochliobolus sativus and Puccinia recondita f. sp. tritici. The inclusion of chitin in the form of dry powder or chitin and chitosan in the form of a colloidal suspension into the medium for deep cultivation of bacteria showed that only colloidal chitin increased the antagonistic activity of B. subtilis strains against test cultures of Alternaria solani and Clavibacter michiganensis. The ability of B. subtilis strains to synthesize extracellular chitinase when cultivated in a medium containing colloidal chitin was established. A higher fungistatic effect of the laboratory sample Vitaplan CL + colloidal chitin against Cohliobolus sativus was revealed as compared to the original sample. It was shown that the laboratory sample Vitaplan, CL + colloidal chitin increases the resistance of wheat to dark brown spot and brown rust 1.5–2.0 times more effectively as compared to Vitaplan, CL. As a result of the research, a laboratory sample of Vitaplan, CL + colloidal chitin was obtained with increased antagonistic and inducing activity as compared to Vitaplan, CL.

Aqueous Chemical Co-Precipitation of Iron Oxide Magnetic Nanoparticles for Use in Agricultural Technologies

Magnetic nanoparticles of iron oxides were obtained by precipitation from aqueous solutions of iron chlorides (Fe2+/Fe3+). It is shown that, depending on the use of various technological techniques in their synthesis (ultrasound, bubbling with argon, heating, the addition of oleic acid), nanoparticles 5-40 nm in size, spherical or plate-like, with a specific surface area of 52-92 m2/g, are formed corresponding to maghemite or solid solutions of maghemite with magnetite. The latter, in particular, are synthesized with a shell of oleic acid. Aqueous suspensions of nanoparticles (0.00001 to 100 mg/L) were used for the pre-sowing treatment of seeds of spring barley, cabbage, and salad crops, as well as for foliar treatment (0.001 to 1 mg/L) of vegetative cucumber and lettuce plants. It was found that these nanoparticles do not possess fungicidal and bactericidal activity against pathogens (Xanthomonas campestris pv. campestris (Pammel) Dowson) of cabbage vascular bacteriosis, barley dark brown spot, and root rot (Cochliobolus sativus (S. Ito & Kurler ex.) Drechs. Dastur), but exhibit weak fungicidal activity in certain concentrations, in particular, against the causative agents of blackleg in white cabbage. Presowing seed treatment, in general, has a positive effect on germination and morphometric parameters of different plants. These parameters significantly depend on the concentration of nanoparticles in suspensions, their phase composition, and the presence or absence of an inert shell on the surface. Foliar treatments of cucumber and lettuce seedlings with suspensions of synthesized nanoparticles improved the morphometric and biochemical parameters of plants, which together provide a tendency to increase their productivity, which is more pronounced at a nanoparticle concentration of 0.01 mg/L. In the future, it is possible to further enhance the phytoprotective effect of iron oxide nanoparticles, which will reduce the dose load of persistent agrochemicals and pesticides on the environment.

A new species of Amazonian snouted treefrog (Hylidae:Scinax) with description of a novel species-habitat association for an aquatic breeding frog

The genusScinaxis one of the most specious genera of treefrogs of the family Hylidae. Despite the high number of potential new species ofScinaxrevealed in recent studies, the rate of species descriptions for Amazonia has been low in the last decade. A potential cause of this low rate may be the existence of morphologically cryptic species. Describing new species may not only impact the taxonomy and systematics of a group of organisms but also benefit other fields of biology. Ecological studies conducted in megadiverse regions, such as Amazonia, often meet challenging questions concerning insufficient knowledge of organismal alpha taxonomy. Due to that, detecting species-habitat associations is dependent on our ability to properly identify species. In this study, we first provide a description of a new species (including its tadpoles) of the genusScinaxdistributed along heterogeneous landscapes in southern Amazonia; and secondly assess the influence of environmental heterogeneity on the new species’ abundance and distribution.Scinax ruberoculatussp. nov. differs from all nominal congeners by its small size (SVL 22.6–25.9 mm in males and 25.4–27.5 mm in females), by having a dark brown spot on the head and scapular region shaped mainly like the mothCopiopteryx semiramis(or a human molar in lateral view, or a triangle), bicolored reddish and grey iris, snout truncate in dorsal view, bilobate vocal sac in males, by its advertisement call consisting of a single pulsed note with duration of 0.134–0.331 s, 10–23 pulses per note, and dominant frequency 1,809–1,895 Hz. Both occurrence and abundance of the new species are significantly influenced by silt content in the soil. This finding brings the first evidence that edaphic factors influence species-habitat association in Amazonian aquatic breeding frogs.

A new species of Choroterpes Eaton, 1881 (Ephemeroptera: Leptophlebiidae) from India

A new species of Choroterpes Eaton, 1881 is described based on the larvae from India. Choroterpes (Choroterpes) kaegies sp. n. can be distinguished from other known species of the subgenus by the following combination of characters: (i) anteromedian emargination of labrum broad; (ii) each femur with a dark brown spot at middle and near apex; (iii) gill 1 single and slender and (iv) upper and lower lamellae of gills 2–7 with 3 apical processes, median process relatively slender and longer than laterals. A key to the known species of Choroterpes Eaton, 1881 in India is also provided.

Pentatomids associated with blackberry

Information concerning the presence of stink bugs in blackberry (Rubus spp.) in Brazil is sparse. This study aimed to identify the stink bug species associated with blackberry, to establish the daily dynamics and evaluate the fruits damage. The experiment was conducted in Santa Maria, Rio Grande do Sul State, Brazil, in blackberry orchard. Presence and evaluations of stink bugs were done weekly through visual and sweeping samplings at different day times. Five species of pentatomids were identified: Piezodorus guildinii, Nezara viridula, Euschistus heros, Dichelops furcatus and Edessa meditabunda. The bugs attack the drupelets producing a dark brown spot and wrinkled berries.

A NEW SPECIES OF BUCCULATRIX

Bucculatrix Ainsliella, n. sp.—Antennæ about the fithts the length of the fore wings, annulated in dusky brown and dull yellow. Eye caps golden white, expanded. Apical tuft long, projecting foward, dark brown in centre, shading outwardly to dingy white. Face satiny cream white. Thorax cream white, more or less dusky, overlaid with dark brown scales, with small but distinct dark brown spot on centre of dorsum, two rather narrow marks of same colour forming a triangle or open V on posterior joint, back of which is a silvery white band.