Insecticidal activity of spray dried microencapsulated essential oils of Rosmarinus officinalis and Zataria multiflora against Tribolium confusum. (February 2020)

• Record Type: Journal Article
• Authors: Ahsaei, Seyed Mohammad; Rodríguez-Rojo, Soraya; Salgado, Marta; Cocero, María José; Talebi-Jahromi, Khalil; Amoabediny, Ghassem
• Is Part Of: Crop protection. Volume 128(2020)
• Publication Date: 2020-02
• Subjects: Essential oil -- Microcapsules -- Stored product pest -- Rosemary -- Zataria -- OSA-Starch; Plants, Protection of -- Periodicals; 632.05
• DOI: 10.1016/j.cropro.2019.104996
• Languages: English
• ISSNs: 0261-2194

Abstract

Abstract: Rosmarinus officinalis and Zataria multiflora (Lamiaceae) essential oils (EOs) contain components with insecticidal properties that can be used as pesticides for stored product pests. In the present study, they were encapsulated in octenyl succinic anhydride (OSA) - starch in order to test their insecticidal activity against Tribolium confusum . First an oil-in-water emulsion was prepared and afterwards, it was dried by spray-drying technique. The emulsions were characterized regarding particle size (461–854 nm), stability and encapsulated oil efficiency (68–88%). Also, solid formulations were characterized by particle size (8.29–11.35 μm), encapsulation efficiency (5–52%) and water activity (0.19–0.26). Further, the release rate at storage conditions (at 27 ± 3 °C and 70–75% relative humidity in the dark) was measured over a period of 40 days. The insecticidal activity against T. confusum was determined by specific bioassays performed at 27 ± 3 °C temperature and 70–75% relative humidity in the dark. Five concentrations were used for estimation of fumigant toxicity of rosemary and Zataria oils after 72 h exposure in adult beetles. Fumigant toxicity results revealed that microencapsulated oils were more effective than non-formulated oils against beetles in long time. Similarly, it was demonstrated that microencapsulation of the essential oils increases their persistence: non-formulated oils have not insecticidal activity after 15 days of the storage period, whereas at the same period, the mortality rate against T. confusum of rosemary and Zataria microencapsulated oils was 46.6 and 35.5%, respectively. Highlights: Essential oils microcapsules (EOs-MC) provide controlled release properties. Rosemary EO formulations proved to be more effective than Zataria ones. Rosemary MC produced 60% mortality of Tribolium confusum vs 10% of EO after 25 days. Microencapsulation of EOs is a useful tool for controlling pest of stored products.