Mg-LDH Nanoclays Intercalated Fennel and Green Tea Active Ingredient: Field and Laboratory Evaluation of Insecticidal Activities against Culex pipiens and Their Non-Target Organisms

Abstract

(1) Background: Mosquito control with essential oils is a growing demand. This work evaluated the novel larvicidal and adulticidal activity of fennel and green tea oils and their Layered double hydroxides (LDHs) nanohybrid against Culex pipiens (Cx. pipiens) in both laboratory and field conditions and evaluated their effect against non-target organisms; (2) Methods: Two types of nanoclays, MgAl-LDH and NiAl-LDH were synthesized and characterized using PXRD, TEM and SEM, whereas their elemental analysis was accomplished by SEM-EDX; (3) Results: Mg and Ni LDHs were synthesized by the co-precipitation method. The adsorption and desorption of active ingredients were conducted using LC MS/MS, with reference to the SEM-EXD analysis. The desorption process of MgAl-LDH intercalated green tea oil was conducted using ethanol, and reveled significant peaks related to polyphenols and flavonoids like Vanillin, Catechin, Daidzein, Ellagic acid, Naringenin, Myricetin and Syringic acid with concentrations of 0.76, 0.73, 0.67, 0.59, 0.52, 0.44 and 0.42 μg/g, respectively. The larvicidal LC50 values of fennel oil, Mg-LDH-F, and Ni-LDH-F were 843.88, 451.95, 550.12 ppm, respectively, whereas the corresponding values of green tea were 938.93, 530.46, and 769.94 ppm. The larval reduction percentage of fennel oil and Mg-LDH-F reached 90.1 and 96.2%, 24 h PT and their persistence reached five and seven days PT, respectively. The reduction percentage of green tea oil and Mg-LDH-GT reached 88.00 and 92.01%, 24 h PT and their persistence reached five and six days PT, respectively. Against adults, Mg-LDH-GT and Ni-LDH-GT were less effective than green tea oil as their LC95 values were 5.45, 25.90, and 35.39%, respectively. The reduction in adult density PT with fennel oil, Mg-LDH-F, green tea oil, and Mg-LDH-GT reached 83.1, 100, 77.0, and 99.0%, respectively, 24 h PT and were effective for three days. Mg-LDH-GT and Mg-LDH-F increased the predation Cybister tripunctatus (71% and 69%), respectively; (4) Conclusions: For the first time, Mg-LDH-GT and Mg-LDH-F was the best system loaded with relatively good desorption release to its active ingredients and significantly affected Cx. pipiens larvae and adults in both laboratory and field circumstances, and it could be included in mosquito control.

Novel Pesticidal Efficacy of Araucaria heterophylla and Commiphora molmol Extracts against Camel and Cattle Blood-Sucking Ectoparasites

“…Botanicals have been well-known for their medicinal properties [24] since ancient times [25] and induce anthelmintic, antiprotozoal, antiviral, antifungal, and antibacterial [26][27][28][29][30][31][32] and pesticidal effects [14,15] such as ovicidal [33,34], larvicidal and insect growth regulating effects [19,[35][36][37][38][39][40][41][42][43][44][45][46][47][48] as well as adulticidal and repellent properties [8,33,34,39,45,46,[49][50][51][52][53]. Botanicals are characterized by high efficiency against pests and prevention of their associated diseases, safety to non-target organisms [5,10,44], and biodegradation [5,11].…”

Mg–Al LDH nanosheets as a nanotechnological tool in agriculture: an exploratory toxicity evaluation study

“…, where M 2+ is a divalent metal cation (e.g., Mg 2+ , Ni 2+ , or Zn 2+ ), M 3+ is a trivalent metal cation (e.g., Al 3+ , Fe 3+ , or Cr 3+ ), A n− represents the interlayer inorganic or organic anions that compensate the charge (e.g., ), and x is a calculated ratio between M(II)/ M(III) + M(II), with values ranging from 0 to 0.4. 28 Among their relevant characteristics, those related to their adsorption/ desorption and thermal stability properties have captivated researchers' attention because they can be used in drug delivery, 21,29 adsorbents, 30 catalysts, 31 and fire retardants. 25 Although Mg-Al LDH has been proposed and probed as a delivery system for pathogen control compounds and plant fertilizers in different organisms, 24,29,32,33 these studies do not focus directly on the toxicity of the nanostructure itself on target organisms; instead, they evaluate the general effect that involves other components, making its possible toxicological effect hard to establish.…”

“…, NO 3 − , CO 3 2− , or SO 4 2− ), and x is a calculated ratio between M( ii )/M( iii ) + M( ii ), with values ranging from 0 to 0.4. 28 Among their relevant characteristics, those related to their adsorption/desorption and thermal stability properties have captivated researchers' attention because they can be used in drug delivery, 21,29 adsorbents, 30 catalysts, 31 and fire retardants. 25…”

Larvicidal and Biochemical Effects of Some Essential Oils and Bee Products Against Culex pipiens Larvae (Diptera: Culicidae)

“…In Egypt, mosquito species showed different levels of resistance against chemical insecticides (Tageldin, R.A. et al, 2018;El-Hosainy et al, 2018;Abdelbaset B. Zayed et al, 2019;Meshrif et al, 2021). There are several alternatives to chemicals including botanicals and plant-based insecticides which are ecofriendly and have toxic, growth-reducing and repellent effects against insects (Regnaultroger et al, 2012;Zahran et al, 2017;Baz et al, 2021;Baz et al, 2022a, b;Radwan et al, 2022).…”