Biological activity of tannins extracts from processed Camellia sinensis (black and green tea), Vicia faba and Urtica dioica and Allium cepa essential oil on three economic insects

Abstract

Nowadays to move toward a more sustainable agriculture, use of pesticide alternatives that have positive effects and play critical roles toward reducing the use of pesticides should be used. Laboratory bioassays were carried out to analyze the bioactivity of tannins isolated from urtica weed leaves (U), bean hull (B), black tea (BT) and green tea (GT) against larvae of cotton leafworm Spodoptera littoralis (Boisduval) using food mixing technique and essential oil isolated from onion against larvae of cotton leafworm, adults of rice weevil and houseflies using fumigation technique. The results showed that during the first week of treatment, tannins extracted from U had the strongest antifeedant activity with an EC50 of 33.034 μg/g followed by tannins extracted from B (EC50 = 47.839 μg/g). In the second and third week, tannins isolated from B depicted highest antifeedant activity (EC50 = 37.733 and 84.828, respectively). Furthermore, the isolated tannins induced notable larval growth inhibition on S littoralis. On the other hand, mortality percentage of onion essential oil on tested insects clearly increased with both increased concentration and exposure time. The LC50 (μg/cm3) at 30 min reflected that the essential oil had a greater toxicity to cotton leafworm with a LC50 = 2.15 μg/cm3 while least toxic to house flies (LC50 = 16.09). The repellency action based on LT50 values was seen to be highly effective in houseflies (LT50 = 1.85 min). The results demonstrated that tannins and essential oil could be applicable in the management of insect pests to decrease ecologically detrimental effects of synthetic insecticides.

Efficiency of Citrus limon L. Ripe Peel Extract In The Control of Raoiella indica (HIRST, 1924) (Prostigmata: Tenuipalpidae)

“…The tannins, the compounds with more expressive concentration in the C. limon extract, are constituted by complex structure molecules (BULE et al, 2020;SAHAKYAN et al, 2020), which permits the easier interaction with proteins, enzymes and alkaloids (EMAM & IBRAHIM, 2020), so that their different forms can have different biochemical effects in herbivore arthropods, causing mortality and deterrence (CHEN et al, 2022). Therefore, tannins can act as endogenous growth inhibitors (EL-ASWAD et al, 2023), anti-nutritional substances and can also act in the defense against biotic and abiotic stresses (PRATYUSHA, 2022). In situations of herbivore animals and pathogens attacking, the plants can produce phenolic compounds as a method of repelling harmful species or attracting natural enemies species (CHOWDHARY et al, 2021).…”

Toxicity of Bioactive Compounds of Strychnos pseudoquina (Loganiaceae) in Spodoptera frugiperda (Noctuidae)

“…These secondary metabolites are commonly found in S. pseudoquina barks [26]. According to Taiz and Zeiger and El-Aswad et al [36,37], tannins are phenolic compounds with defense properties produced by plants that are potentially toxic and have antifeedant action for many herbivores.…”

Olfactometric response of selected crop pests to the scent of common nettle (Urtica dioica L.) and the influence of aqueous plant extracts on their behavior

“…The beneficial effects of extracts from this plant on the human organism are extensively recognized (Dhouibi et al 2020;Bhusal et al 2022). Furthermore, extracts from both fresh and dried nettle leaves exhibit insect-repelling properties, suppress the development of various plant diseases, and are considered safe for use (Taadaouit et al 2012;Thakur et al 2012;El-Aswad et al 2023). While alcoholic extracts and essential oils typically demonstrate higher insecticidal efficacy compared to water extracts, the former are more complex and expensive to prepare (Baran et al 2020;Bhardwaj et al 2020;Suteu et al 2020).…”