Evaluation of Streptomyces saraciticas as Soil Amendments for Controlling Soil-Borne Plant Pathogens

Soil-borne diseases are the major problems in mono cropping. A mixture (designated LTM-m) composed of agricultural wastes and a beneficial microorganism Streptomyces saraceticus SS31 was used as soil amendments to evaluate its efficacy for managing Rhizoctonia solani and root knot nematode (Meloidogyne incognita). In vitro antagonistic assays revealed that SS31 spore suspensions and culture broths effectively suppressed the growth of R. solani, reduced nematode egg hatching, and increased juvenile mortality. Assays using two Petri dishes revealed that LTM-m produced volatile compounds to inhibit the growth of R. solani and cause mortality to the root knot nematode eggs and juveniles. Pot and greenhouse tests showed that application of 0.08% LTM-m could achieve a great reduction of both diseases and significantly increase plant fresh weight. Greenhouse trials revealed that application of LTM-m could change soil properties, including soil pH value, electric conductivity, and soil organic matter. Our results indicate that application of LTM-m bio-organic amendments could effectively manage soil-borne pathogens.

Intraplant Distribution, Preferred Sites, and Damage Caused by Euschistus heros (Hemiptera: Pentatomidae) on Cotton

This study investigated (a) the intraplant distribution of Euschistus heros (F.) (Hemiptera: Pentatomidae) in cotton, (b) its preference for different structures and areas of the cotton plant, and (c) the damage caused at different levels of infestation. Our results determined that, regardless of the time of day, E. heros adults significantly preferred the middle third of cotton plants in comparison to the upper and lower areas (F = 30.221; df = 2; P = 0.001). The adults were present on all cotton structures, and numbers were significantly higher on bolls and leaves/branches (F = 25.333; df = 5; P = 0.001) than on flower buds and flowers. In greenhouse tests, fiber yield, number of bolls per plant, and number of internal punctures in bolls responded significantly to increasing infestation levels of E. heros adults. Damage and yield reduction was observed at 1.5 to 2.0 adults/plant, indicating that an action threshold of 1 adult per plant should be adopted to avoid economic losses. Sampling during boll development should be by either whole-plant inspection or beat cloth methods between 0600 and 1800 h.

Design, Synthesis, and Acaricidal Activity of Phenyl Methoxyacrylates Containing 2-Alkenylthiopyrimidine

A series of novel phenyl methoxyacrylate derivatives containing a 2-alkenylthiopyrimidine substructure were designed, synthesized, and evaluated in terms of acaricidal activity. The structures of the title compounds were identified by 1H NMR, 13C NMR and high-resolution mass spectra (HRMS). Compound (E)-methyl 2-(2-((2-(3,3-dichloroallylthio)-6-(trifluoromethyl)pyrimidin-4-yloxy)methyl)phenyl)-3-methoxyacr-ylate (4j) exhibited significant acaricidal activity against Tetranychus cinnabarinus (T. cinnabarinus) in greenhouse tests possessing nearly twice the larvicidal and ovicidal activity compared to fluacrypyrim. Furthermore, the results of the field trials demonstrated that compound 4j could effectively control Panonychuscitri with long-lasting persistence and rapid action. The toxicology data in terms of LD50 value confirmed that compound 4j has a relatively low acute toxicity to mammals, birds, and honeybees.

EFFECTS OF DOUBLE V-SHAPED OPENERS WITH FURROW COMPACTION FUNCTION ON SEEDBED CHARACTERISTICS AND SOYBEAN EMERGENCE UNDER DOUBLE ROW RIDGE CULTIVATION TECHNIQUE

Based on the technical characteristics of double-row ridge planting, a double V-shaped opener with the furrow compaction function was designed. This opener with the sliding knife and profiling mechanism was capable of furrow opening, compacting and profiling, and thereby created excellent seedbeds with tight bottom and soft soils. Through sunlight greenhouse tests, the effects of the double V-shaped opener on seedbed characteristics and soybean emergence were studied under the compaction forces of T1 (0 N), T2 (500 N), T3 (600 N) and T4 (700 N). The furrow compaction planting significantly affected the seedbed characteristics and soybean emergence and could preserve soil moisture in seedbeds. Under the semiarid condition, the average emergence time under T2 was 0.79 day earlier than under T1, and the emergence rates under T2, T3 and T4 were significantly raised. The seedling height uniformity under T2 was 5.34% higher than under T1. The average emergence time ranked from early to later as T3<T4<T2. The deep seeding uniformity, the emergence uniformity and the average seedling height were all improved as the furrow compaction force was enlarged within 500-700 N. Furrow compaction could preserve soil moisture in seedbeds, and the seedbed soil physical properties and soybean seedling emergence were optimized under the furrow compaction force of 600-700 N.

A novel nano-formulation to reduce the environmental dispersion of herbicides

&lt;p&gt;The use of pesticides in agriculture has numerous advantages but also significant environmental drawbacks; The uncontrolled or excessive use of agrochemicals has progressively contributed to the contamination of environmental matrices, and in particular of soils and groundwater. To contribute solving these issues, an eco-compatible nano-formulation was recently developed by the authors to help controlling the environmental dispersion of Dicamba, a herbicide widely used to control broadleaf weeds; Dicamba is highly soluble and moderately volatile, but is less toxic and persistent compared to other competing herbicides. The proposed nano-formulation was developed using eco-compatible, low-cost materials, including natural clays an biopolymers, with the aim to reduce Dicamba volatilization (thus reducing dispersion in air, and consequently potential impacts on both workers and neighboring crops) and solubility (thus reducing infiltration during and after application, and consequently uncontrolled dispersion in the subsoil). &amp;#160;In this work, the results of laboratory and greenhouse tests are discussed, comparing the efficacy of the nano-formulation against the pure herbicide compound and a commercial Dicamba-based product, in terms of volatilization, mobility in porous media (both saturated and unsaturated) and efficacy in weed control. The column tests results are modeled using colloid transport software (namely MNMs and Hydrus) and used for the development of a preliminary field-scale model of herbicide application and dispersion in the subsoil. The work was developed in the framework of the project Nanograss, co-funded by Compagnia di San Paolo Foundation.&lt;/p&gt;

Pectin-Rich Amendment Enhances Soybean Growth Promotion and Nodulation Mediated by Bacillus Velezensis Strains

Plant growth-promoting rhizobacteria (PGPR) are increasingly used in crops worldwide. While selected PGPR strains can reproducibly promote plant growth under controlled greenhouse conditions, their efficacy in the field is often more variable. Our overall aim was to determine if pectin or orange peel (OP) amendments to Bacillus velezensis (Bv) PGPR strains could increase soybean growth and nodulation by Bradyrhizobium japonicum in greenhouse and field experiments to reduce variability. The treatments included untreated soybean seeds planted in field soil that contained Bv PGPR strains and non-inoculated controls with and without 0.1% (w/v) pectin or (1 or 10 mg/200 μL) orange peel (OP) amendment. In greenhouse and field tests, 35 and 55 days after planting (DAP), the plants were removed from pots, washed, and analyzed for treatment effects. In greenhouse trials, the rhizobial inoculant was not added with Bv strains and pectin or OP amendment, but in the field trial, a commercial B. japonicum inoculant was used with Bv strains and pectin amendment. In the greenhouse tests, soybean seeds inoculated with Bv AP193 and pectin had significantly increased soybean shoot length, dry weight, and nodulation by indigenous Bradyrhizobium compared to AP193 without pectin. In the field trial, pectin with Bv AP193 significantly increased the shoot length, dry weight, and nodulation of a commercial Bradyrhizobium japonicum compared to Bv AP193 without pectin. In greenhouse tests, OP amendment with AP193 at 10 mg significantly increased the dry weight of shoots and roots compared to AP193 without OP amendment. The results demonstrate that pectin-rich amendments can enhance Bv-mediated soybean growth promotion and nodulation by indigenous and inoculated B. japonicum.

Análisis Microbiológico de Biosólidos para su aprovechamiento en cultivos de tallo corto

Sludge and biosolids samples were analyzed microbiologically according to NOM-004-SEMARNAT-2002, of the Intermunicipal System of Wastewater Treatment and Disposal of the municipalities of Rincon (SITRATA) for a period of 10 months in 2017, the most were found within the LMP according to regulations. In addition, it was detected that the use of peracetic acid in doses greater than 0.1 % v/v may be an alternative disinfection in its use in sludge, to reduce the microbiological load, before being used in crops. Physicochemical analyzes were performed on samples of mud and soil to determine their N and P content, finding that the solid mud has 1.19 % of N and 3.51 % of P2O5 determined on a dry basis; which correspond to high values of these macronutrients, essential for crops. Greenhouse tests were carried out with application doses of 0 to 100 percent by weight of biosolids incorporated into the soil, to measure the crop yield of radish (Raphanus sativus), onion (Allium cepa) and carrot (Daucus carota), resulting in Agronomic dose of 20 % w/w the highest yield.

Rapid Detection of Horseweed and Black Picker Sensitivity Levels to Saflufenacil

ABSTRACT: Resistance to herbicides is one of the main factors responsible for weed control failures. Once uncontrolled and stressed, resistant weeds demand a new application of herbicides from different modes of action, which results in higher monetary costs and environmental impact. Knowledge of weed sensitivity levels to herbicides before making decisions for their management in the field is paramount to increasing the efficiency of integrated weed management. Thus, methods that allow the rapid determination of sensitivity levels can help to the correct recommendation before the application, and thus, favor the greater technical, economic and environmental efficiency of weed management. The objective of this work was to validate a rapid method to detect the levels of sensitivity of black picker (Bidens pilosa) and horseweed (Conyza sumatrensis) to saflufenacil. Dose-response experiments were performed in growth chamber, greenhouse and field. The control provided by different doses of the saflufenacil herbicide was evaluated in each environment, and the results correlated within each species. The results showed a significant positive correlation for the results obtained in growth chamber and greenhouse for black picker and horseweed. These results indicate that the method developed in the growth chamber can replace greenhouse tests for determination of the sensitivity of black picker and horseweed to saflufenacil.

Screening of potato varieties for multiple resistance to Synchytrium endobioticum in the western region of Ukraine

Aim. To evaluate potato breeding material for resistance to pathotypes of Synchytrium endobioticum (Schilbersky) Percival (1909) known to be present in Ukraine (pathotypes 1(D 1 ), 11, 13, 18 and 22); to identify resistant registered and potential varieties for the usage in the national wart disease eradication programs and to recommend these se- lected (potential and registered) potato varieties for the breeding program targeted on the development of multiple resistance against pathotypes of S. endobioticum present in Ukraine. Methods. Evaluation of the potato breeding material and registered potato varieties for the resistance against common pathotype 1 (D 1 ) and four aggressive pa- thotypes of S. endobioticum (pathotypes 11, 13, 18 and 22) in climatic chamber and greenhouse tests of Ukrainian Scientifi c Research Plant Quarantine Station of Institute of Plant Protection NAAS (Boyany, Ukraine) following the Spieckermann and Glynne-Lemmerzahl methods (EPPO Standard PM7/28(2)). Field trials on naturally infected soils were conducted according to standard methods adapted to national requirements in the area of Chernivtsi, Zakarpattia and Ivano-Frankivsk regions. Results. 3,736 samples of potato breeding material from six breeding institutions of Ukraine were tested for resistance against S. endobioticum during 2011–2017 in the western region of the country. Among all samples tested, 3,389 were identifi ed as resistant to the widely spread pathotype 1 in the preliminary climatic chamber and greenhouse tests, and 130 of them proved to be resistant under fi eld conditions. Five out of 41 Ukrainian registered potato varieties (Bazys, Hlazurna, Solokha, Bozhedar and Santarka) were found to be resistant to all 5 pathotypes tested (1 (D 1 ), 11, 13, 18 and 22). Conclusions. The 130 samples of potato breed- ing material (which were found to be resistant against the common pathotype 1 of S. endobioticum in the laboratory, greenhouse as well as in the fi eld trials) were recommended for the state variety registration and further usage in an eradication program to localize potato wart outbreaks of the western part of Ukraine. The screening tests revealed that the national breeding program targeted on resistance against S. endobioticum pathotype 11 was the most effec- tive (49 % of samples tested proved to be resistant against this pathotype), whereas it was the least effective against pathotype 18, namely only 30 % of samples resistant. It was speculated that such a dissimilarity may be related to the differences in the genetic material used in the breeding process at various institutions, and which may be the subject of further analysis in order to improve the results of breeding programs. The already registered potato variet- ies Bazys, Hlazurna, Solokha, Bozhedar and Santarka which were found to have a multiple resistance to common pathotype 1 and four local aggressive pathotypes of S. endobioticum (11, 13, 18 and 22) were recommended for use in the breeding process as sources of resistance and also for the eradication programs in the western region of Ukraine, where S. endobioticum is mostly distributed (2409 hectares or 98 %).

Response of winter wheat cultivars to artificial infection with Pyrenophora tritici-repentis in field and greenhouse conditions

The response of 22 winter wheat cultivars to artificial infection with Pyrenophora tritici-repentis has been studied in the field conditions for three years and in the greenhouse conditions as well. The set of cultivars included the cultivars registered in the Czech Republic and Swiss cultivar Arina known for satisfactory resistance to different foliar and head blights. High level of field resistance to Pyrenophora tritici-repentis was detected in cultivars Arina, Vlasta, Rialto, Athlet, Trane, Siria, Vega, Alana, Samara. Not all cultivars showed similar reaction in field and greenhouse tests. Correlation between results of the field and the greenhouse tests was significant for 18 of 22 cultivars. Arina, Vlasta and Vega showed acceptable field resistance and high resistance in the greenhouse tests to Pyrenophora tritici-repentis too. The greenhouse experiments helped to differentiate between examined isolates collected from the territory of the Czech Republic. Cultivar reaction to isolates No. 98001, 98007, 98010, 00071 correlated significantly with the field results.