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Abstract

Repellent usage against rodents is almost not provided anymore. Permission to use many rodent repellent substances under European Union (EU) plant protection regulations has not been renewed in recent years. Some approval for chemical substances have not been renewed due to their toxicological properties, and for some biorational approvals have also not been renewed due to lack of financial support together with other concerns. Some other rodent repellent substances possessing accurate properties in a secondary way have also been withdrawn. Thus, the use of almost ten active substances is now illegal. The lack of support and the resultant orphan use may be explained by the relatively small market and possible business together with the expectations of modern substance application requirements. As a result, the opportunity to consider new biorational substances as candidates is therefore open. Plant based food substances are preferred candidates for plant protection considering their favourable toxicological characteristics. Capsicum oleoresin, a mixture obtained from two spice species (Capsicum annuum and C. frutescens), is one of them with appropriate repellent properties. An application under EU Plant Protection Product regulation has recently been submitted and may become a new repellent for biological control agent against seed predators.

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Authors and Affiliations

Mathilde Stefanini
Mathilde Charon
Patrice André Marchand
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Abstract

This study investigates the acaricidal, ovicidal, and repellent effects of the Tagetes patula Linn. (Asteraceae) leaf extract against both the adult female and egg stages of Tetranychus urticae Koch (Trombidiformes: Tetranychidae) under laboratory conditions. The Tagetes patula ethanolic leaf extract [TpEtOH70%] was screened for adulticide and ovicide bioassays in order to consider its acute toxicity. One sublethal concentration was used to assess egg-laying capacity (fecundity), repellent, and oviposition deterrent activities. The chemical characterization was conducted by gas chromatography-mass spectrometry (GC-MS) analysis to identify the TpEtOH70% bioactive components. Results showed that the LC50 value of TpEtOH70% leaf extract predicted by Probit analysis against T. urticae adult females at 24 h was 0.99%. The TpEtOH70% leaf extract showed a significant toxic effect as the highest mean mortality rates (± SE) of the treated adult females was 88.9 ± 3.7%. However, the TpEtOH70% leaf extract was insignificant in affecting the egg-laying capacity of the adult females treated with a sublethal dose of 0.5% even after 72 h. The TpEtOH70% leaf extract was classified repellent since the repellent index (RI) value was lower than 1 – SD. In addition, it had a high oviposition deterring effect based on a 100% reduction of the total number of eggs. The TpEtOH70% leaf extract had a significant ovicidal effect on T. urticae eggs, with 56.04% reduction in hatching. Five bioactive compounds from various classes of phytochemicals were identified in the TpEtOH70% leaf extract and the major compound was phytol (62.72%). This pioneering investigation reveals the adulticidal, ovicidal, and repellent activities of the TpEtOH70% leaf extract against T. urticae. A combination of multiple modes of action of different plant components may act alone or in synergism to delay the development of mite resistance.

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Authors and Affiliations

Manal Sayed Mohamed Ismail
Hend Maroof Tag
Marguerite Adly Rizk
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Abstract

Natural stones are used as coating material on the exteriors and terraces of buildings in architecture, and in places such as entrances, halls, living rooms, kitchens, bathrooms and stairs in interior spaces. Limra limestone and travertine are used as natural building materials in many structures depending on their colors. However, the water absorption values of these two natural stones are high due to their porosity, resulting in negative effects from atmospheric conditions. In this study, two different carbonate-based natural stones, limra limestone and travertine, were treated with two different water-repellent chemicals, one solvent-based and one water-based. After application, thermal shock tests were performed with a sodium chloride solution consisting of twenty cycles. The changes in the weights of samples dried to constant mass, ultrasonic permeability, Leeb hardness, and color change values in the samples were determined after the thermal shock tests. In addition, the effects of water-repellent chemicals on the formation of NaCl crystals accumulated in the pores of the rocks were examined by SEM and EDX analysis. Changes in non-destructively measured values were compared with the values of reference samples without surface protection. The solvent- based water-repellent chemical made the sample surface more hydrophobic than the water-based repellent. In both types of natural stones, the solvent-based water repellent chemical showed more protective properties against salt crystallization under thermal shock conditions compared to the water-based repellent.
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Authors and Affiliations

Gökhan Ekincioğlu
1
ORCID: ORCID

  1. Kırşehir Ahi Evran University, Kaman Vocational School, Department of Mining and Mineral Extraction,Turkey

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