Toxicological, biological, and biochemical impacts of the egyptian lavender (Lavandula multifida L.) essential oil on two lepidopteran pests

The use of essential oils as an eco-friendly tool in pest management stems from their natural origin and the presence of bioactive compounds that exhibit pesticidal properties, offering a sustainable alternative to synthetic chemical pesticides. This study explores the toxicity of Lavandula multifida (lavender) essential oil (EO), as a botanical pesticide against two widespread and destructive Noctuidae pests, Spodoptera littoralis (Boisd.) and Agrotis ipsilon (Hufnagel). GC-MS was employed to characterize 23 compounds in the EO, with 1,3,3-trimethyl-2-oxabicyclo [2.2.2] octane (eucalyptol) (39.84%), being the primary component. The leaf dipping technique was utilized to assess the toxicity of the EO to both insects. At 96 hours post-treatment, the LC50 of lavender EO to S. littoralis and A. ipsilon larvae were 2.350 and 2.991 mg · ml–1, respectively. Concerning its biological effect, both concentrations of the EO (LC15 and LC50) significantly shortened the duration of the larval (to 15.24 and 14.23 days) and pupal (to 11.19 and 10.55 days) stages of S. littoralis. Biochemical assays revealed that the LC50 of lavender EO significantly inhibited α-esterase activity in S. littoralis at 72- and 96 hours post-treatment (0.031 and 0.063 mmol · min–1 · mg–1), and A. ipsilon at 96 hours post-treatment (0.129 mmol · min–1 · mg–1 protein). Given its significant toxicological, biological, and biochemical effects on S. littoralis, it is suggested that lavender EO could be considered for use in integrated pest management strategies while ensuring its safe application to protect non-target organisms

Lethal and Sublethal Effects of Cyantraniliprole on the Biology and Metabolic Enzyme Activities of Two Lepidopteran Pests, Spodoptera littoralis and Agrotis ipsilon, and a Generalist Predator, Chrysoperla carnea (Neuroptera: Chrysopidae)

Simple Summary: This study discusses the effects of cyantraniliprole, a new insecticide, on two lepidopteran pests and a biological control agent. Cyantraniliprole showed higher toxicity to one pest species compared to the other, prolonged developmental stages, and increased detoxification activity in both pest species. It also had a negative but slight impact on the biological control agent at the recommended concentrations. The study suggests that cyantraniliprole can effectively control the pests while being compatible with the control agent, but further field studies are needed for validation. Abstract: Cyantraniliprole is a novel anthranilic diamide insecticide registered for controlling chewing and sucking insect pests. Here, the lethal and sublethal effects of this insecticide on two destructive lepidopteran pests, Spodoptera littoralis Boisduval and Agrotis ipsilon Hufnagel, were evaluated. Because the effects of novel insecticides on beneficial and non-target arthropods must be considered, the impact of cyantraniliprole on a generalist biological control agent, Chrysoperla carnea [Stephens 1836], were also examined. Overall, our study revealed that cyantraniliprole was more toxic to A. ipsilon than to S. littoralis. Moreover, the LC15 and LC50 of the insecticide significantly prolonged the duration of the larval and pupal stages and induced enzymatic detoxification activity in both species. Treatment of the second-instar larvae of C. carnea with the recommended concentration of cyantraniliprole (0.75 mg/L) doubled the mortality rates and resulted in a slight negative effect on the biology and detoxification enzymes of C. carnea. Our results indicate that both sublethal and lethal concentrations of cyantraniliprole can successfully suppress S. littoralis and A. ipsilon populations. They also suggest that C. carnea, as a generalist predator, is compatible with cyantraniliprole under the modelled realistic field conditions. In future investigations, insights into the effects of cyantraniliprole on S. littoralis, A. ipsilon, and C. carnea under field conditions will be required to appropriately validate our results

Phytochemical Investigation of Three <i>Cystoseira</i> Species and Their Larvicidal Activity Supported with In Silico Studies

Culex pipiens mosquitoes are transmitters of many viruses and are associated with the transmission of many diseases, such as filariasis and avian malaria, that have a high rate of mortality. The current study draws attention to the larvicidal efficacy of three methanolic algal extracts, Cystoseira myrica, C. trinodis, and C. tamariscifolia, against the third larval instar of Cx. pipiens. The UPLC-ESI-MS analysis of three methanol fractions of algal samples led to the tentative characterization of twelve compounds with different percentages among the three samples belonging to phenolics and terpenoids. Probit analysis was used to calculate the lethal concentrations (LC50 and LC90). The highest level of toxicity was attained after treatment with C. myrica extract using a lethal concentration 50 (LC50) of 105.06 ppm, followed by C. trinodis (135.08 ppm), and the lowest level of toxicity was achieved by C. tamariscifolia (138.71 ppm) after 24 h. The elevation of glutathione-S-transferase (GST) and reduction of acetylcholine esterase (AChE) enzymes confirm the larvicidal activity of the three algal extracts. When compared to untreated larvae, all evaluated extracts revealed a significant reduction in protein, lipid, and carbohydrate contents, verifying their larvicidal effectiveness. To further support the observed activity, an in silico study for the identified compounds was carried out on the two tested enzymes. Results showed that the identified compounds and the tested enzymes had excellent binding affinities for each other. Overall, the current work suggests that the three algal extractions are a prospective source for the development of innovative, environmentally friendly larvicides

Growth Optimization and Rearing of Mealworm (<i>Tenebrio molitor</i> L.) as a Sustainable Food Source

As a sustainable food source for humans, mealworms (Tenebrio molitor) have a great deal of potential, due to the fact that they have a very favorable nutritional profile and a low environmental impact. For meal production, feed formulation and optimization are important. The mealworm Tenebrio molitor (Coleoptera: Tenebrionidae) is the most consumed insect in the world. Mealworms were given a variety of diets, including wheat bran as constant diet supplemented with different levels of Ospor (Bacillus clausii) at 0.002 g, 0.004 g, 0.006 g, and 0.008 g; imutec (Lacticaseibacillus rhamnosus) at 0.2 g. 0.4 g, 0.6 g, and 0.8 g; fungi (Calocybe indica) at 250 g, 500 g, and 750 g; yeast (Saccharomyces cerevisiae) at 50 g, 100 g, and 150 g; and wheat bran (standard diet) were examined in complete randomized design (CRD). Different parameters, i.e., the larval, pupal, and adult weight, size, life span, and nutritional profile of mealworm were studied. When compared with other insect growth promoters, only wheat bran was discovered to be the most efficient. It generated the heaviest and longest larvae at 65.03 mg and 18.32 mm, respectively, as well as pupae weighing 107.55 mg and 19.94 mm, respectively, and adults weighing 87.52 mg and 20.26 mm, respectively. It was also determined that fungi (C. indica) and ospor (B. clausii) promoted faster larval development than yeast (S. cerevisiae) and imutec (L. rhamnosus). Larval mortality was also greater in the imutec (L. rhamnosus) and yeast (S. cerevisiae) diets than the others. No pupal mortality was recorded in all diets. Furthermore, the protein content of Tenebrio. molitor raised on a diet including fungi (C. indica) was the highest at (375 g), with a content of 68.31%, followed by a concentration of (250 g) with a content of 67.84%, and wheat bran (1 kg) (normal diet) with the lowest content at 58.91%. T. molitor larvae fed a diet supplemented with bacterial and fungal had lower fat and ash content than bran-fed T. molitor larvae (standard diet). Wheat bran (normal diet) had the highest fat at 16.11%, and ash at 7.71%. Hence, it is concluded that wheat bran alone or diet containing fungi (C. indica) and ospor (B. clausii) performed better in terms of growth, and these diets and protein content are recommended for the mass rearing of mealworms