Roman Pavela

Bio: Roman Pavela is an academic researcher from Czech University of Life Sciences Prague. The author has contributed to research in topics: Essential oil & Spodoptera littoralis. The author has an hindex of 47, co-authored 148 publications receiving 6892 citations. Previous affiliations of Roman Pavela include Research Institute of Crop Production.

History, presence and perspective of using plant extracts as commercial botanical insecticides and farm products for protection against insects – a review

Abstract: Pavela R. (2016): History, presence and perspective of using plant extracts as commercial botanical insecticides and farm products for protection against insects – a review. Plant Protect. Sci., 52: 229–241. Botanical insecticides keep attracting more attention from environmental and small farmers worldwide as they are considered as a suitable alternative to synthetic insecticides. The use of secondary metabolites in a defensive manner isolated from plants is a tradition more than 3000 years old. However, despite current intensive research, the assortment of suitable commercial products is very limited and insufficient in view of the global rise in the demand for biopesticides. Farm products as well as new basic substances offer an important perspective of being widely used in the protection against harmful insects due to their multiple undoubted benefits. These benefits, which are also drawbacks of botanical insecticides, as well as their history in addition to their presence and perspective are critically reviewed in this paper.

Acute toxicity and synergistic and antagonistic effects of the aromatic compounds of some essential oils against Culex quinquefasciatus Say larvae

Abstract: The efficacy of 30 aromatic compounds and their mutual binary combinations was assessed for acute toxicity against the larvae Culex quinquefasciatus. Based on comparison of the lethal doses, thymol and p-cymene were selected as the most effective (LD50 = 18 and 21 mg L−1, respectively, and LD90 = 25 and 30 mg L−1, respectively). Although the LD50 for terpinolene and trans-anethole was also estimated at 21 mg L−1, their LD90 was significantly higher compared to the substances above (245 and 34 mg L−1, respectively). In total, 435 binary combinations were tested, of which 249 combinations showed a significant synergistic effect, while 74 combinations showed a significant antagonistic effect on mortality. Only nine substances were identified as being able to create a synergistic effect with more than 20 substances: limonene, trans-anethole, 4-allylanisole, carvacrol, isoeugenol, menthone, carvone, borneol, and camphor. The highest synergistic effect on larval mortality was achieved for the combinations: eugenol and isoeugenol, carvone and carvacrol, carvone and 4-allylanisole, carvone and α-terpineol, carvone and menthone, limonene and trans-anethole, limonene and menthone, α-pinene and menthone, β-citronellol and menthone, carvacrol and 4-allylanisole, carvacrol and terpineol, α-terpinene and trans-anethole, camphor and menthone, camphene and menthone, and 4-allylanisole and menthone. Significant differences between achieved mortality and the mutual mixing ratio were found for the five selected binary mixtures that had shown the most significant synergistic effect in the previous tests. The mixture of limonene and trans-anethole showed the highest mortality, with the mixing ratio 1:1; the mixture of eugenol and isoeugenol caused 90.2 % mortality, with the mixing ratio 1:3. One hundred percent mortality was achieved if carvacrol was contained in a mixture with carvone in a ratio >2. After a comparison of all our results, based on our experiments, we can choose two pairs that caused mortality higher than 90 % in concentrations lower than 20 mg L−1: limonene and trans-anethole (with the mixing ratio 1:1), and carvone and carvacrol (with the mixing ratio 1:2–3). The information gained can thus be used in the development of new botanical insecticides based on essential oils (EOs) and particularly in the creation of formulations.

Microencapsulation of Oils: A Comprehensive Review of Benefits, Techniques, and Applications

Abstract: Microencapsulation is a process of building a functional barrier between the core and wall material to avoid chemical and physical reactions and to maintain the biological, functional, and physicochemical properties of core materials. Microencapsulation of marine, vegetable, and essential oils has been conducted and commercialized by employing different methods including emulsification, spray-drying, coaxial electrospray system, freeze-drying, coacervation, in situ polymerization, melt-extrusion, supercritical fluid technology, and fluidized-bed-coating. Spray-drying and coacervation are the most commonly used techniques for the microencapsulation of oils. The choice of an appropriate microencapsulation technique and wall material depends upon the end use of the product and the processing conditions involved. Microencapsulation has the ability to enhance the oxidative stability, thermostability, shelf-life, and biological activity of oils. In addition, it can also be helpful in controlling the volatility and release properties of essential oils. Microencapsulated marine, vegetable, and essential oils have found broad applications in various fields. This review describes the recognized benefits and functional properties of various oils, microencapsulation techniques, and application of encapsulated oils in various food, pharmaceutical, and even textile products. Moreover, this review may provide information to researchers working in the field of food, pharmacy, agronomy, engineering, and nutrition who are interested in microencapsulation of oils.

Biochemistry And Molecular Biology Of Plants

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