Owing to the large quantity of pesticides utilized conventional pesticide formulations can have numerous negative environmental impacts such as side effects on human health and pest resistance development. Using nano-pesticide formulations can minimize the quantity of pesticides used, thereby lowering pest control costs, and environmental contamination. This work used self-emulsifying and solidification technology to convert chlorpyrifos, emamectin benzoate, and beta-cyfluthrin to solid nano-dispersions, all of which were examined for their properties and efficacy against the Egyptian cotton leafworm, Spodoptera littoralis (Boisd.). During the preparation of the formulation mixture, solid nano-dispersion particles with sizes ranging from 7 to 400 nm were developed. With the design of the nano-formulation, there were variations in the active ingredient, carrier, surfactant, and pesticide concentration types. The type of active ingredient, carrier, surfactant, and pesticide concentration varied with the nano-formulation design. The nano-formulation with 1 to 5% pesticides, 8% a combination of Nonyl phenol ethoxylated surfactant (Unitop 100) mixed with Geronol surfactant (FF4), and sucrose as a carrier indicated the best polydispersity index, Z-average, and biological activity. Moreover, the surfactant and solvent content in the solid nano-dispersion formulation was lower than in conventional pesticide formulations. Based on the LC50 values, chlorpyrifos, emamectin benzoate, and beta-cyfluthrin solid nano-dispersions were more toxic (LC50 values were 0.17 and 0.07 for emamectin benzoate, 4.61 and 3.61 for beta-cyfluthrin, and 10.06 and 6.74 mg ∙ l–1 for chlorpyrifos after 24 and 48 h of treatment, respectively) than their conventional formulations (LC50 values were 0.85 and 0.36 for emamectin benzoate nano-dispersion, 19.19 and 15.30 for beta-cyfluthrin nano-dispersion, and 27.01 and 26.17 mg l–1 for chlorpyrifos-nano-dispersion after 24 and 48 h of treatment, respectively) against S. littorralis under laboratory conditions. Under field conditions, chlorpyrifos, emamectin benzoate, and beta-cyfluthrin in nano-dispersion formulations were more effective against cotton leaf worms than the same insecticides in commercial formulation. Thus, nano-formulations could be recommended in pest control where they avoid organic solvents and reduce surfactants, control costs, and environmental pollution.
Cultivation technologies based on the use of microbiological preparations or the introduction of cover crops in organic farming are alternatives to chemical plant protection products. To confirm this hypothesis, field studies were conducted in central Poland in 2019–2022 to determine the effect of bacterial consortia and green fertilizers from cover crops on the dry mass, abundance and species composition of dominant weed species occurring in spelt wheat grown in organic farming. Two factors were researched: I. Bacterial consortia: control treatment (no bacteria), bacterial consortium I (Azotobacter chroococcum + Azospirillum lipoferum Br17), bacterial consortium II (Bacillus megaterium var. phosphaticum + Arthrobacter agilis), bacterial consortium III (Azotobacter chroococcum + Azospirillum lipoferum Br17 + Bacillus megaterium var. phosphaticum + Arthrobacter agilis), II. Cover crops: control treatment (no cover crops), red clover, red clover + Italian ryegrass, and Italian ryegrass. Spelt wheat was harvested in late July. Just before harvesting, weeds were sampled to determine their dry matter, number, and species composition. The research clearly demonstrated that the application of bacterial consortia with cover crops significantly reduced the dry matter and number of weeds, including the dominant species. The greatest reduction in weed number was recorded in treatments after the application of bacterial consortium III in combination with plowing cover crops of red clover and a mixture of red clover and Italian ryegrass.
Tetranychus utricae Koch (the two-spotted spider mite, TSSM) is a major pest of sugar beet plants (Beta vulgaris L.), which quickly develops resistance to miticides. Volatile organic compounds (VOCs) have the potential of providing an environmentally friendly alternative to currently used insecticides. The main goal of this study was to evaluate the changes in the qualitative and quantitative composition of the VOCs released by sugar beet plants under drought conditions, TSSM infestation, or subjected to combined types of stress. Volatiles were collected over a 2 h period on days 2, 3 and 6 following TSSM feeding and/or drought and, following elution, were analyzed by gas chromatography with mass spectrometric detection. In particular, plants that were subjected to combined abiotic and biotic stress resulted in even higher levels of VOCs being released than from plants subjected to a single stress. Ten key volatiles were identified, namely: (Z)-3-hexenal, (Z)-3-hexen-1-ol, (E)-2-hexen-1-ol, (Z)-3-hexen-1-yl acetate, (Z)-ocimene, linalool, β-pinene, (E)-β-farnesene, β-caryophyllene and benzyl acetate. Of these 10, three were emitted with significantly higher quantities than the other seven: β-pinene, β-caryophyllene and benzyl acetate. This suggests that these three volatiles are potentially the most useful as natural alternatives to synthetic miticides to protect sugar beet crops from TSSM. Further research is needed to assess this hypothesis and to determine their activity against the mites.