This study assessed the larvicidal activity of methanol and hexane fruit peel extracts from Hylocereus polyrhizus (red dragon fruit), Citrus sinensis (sweet orange), Punica granatum (pomegranate), Annona cherimola (cherimoya), and Physalis peruviana (groundcherry) against third‐instar larvae of Culex pipiens, following WHO bioassay guidelines. Larval mortality was recorded at 24 and 48 h, and LC50, LC90, and LC95 values were calculated. Methanol extracts demonstrated greater larvicidal activity compared with hexane extracts. The most effective plants were H. polyrhizus, C. sinensis, and P. granatum. Based on 48‐h LC50 values, methanol extract toxicity followed the order: H. polyrhizus (157.73 ppm) < C. sinensis (180.22 ppm) < P. granatum (190.38 ppm) < A. cherimola (249.98 ppm) < P. peruviana (507.68 ppm). For hexane extracts, the ranking was H. polyrhizus (176.57 ppm) < C. sinensis (220.36 ppm) < P. granatum (252.63 ppm) < A. cherimola (307.69 ppm) < P. peruviana (651.06 ppm). GC/MS analysis of the five n‐hexane extracts identified 57 compounds, mainly alkanes, alkenes, aldehydes, esters, ketones, triterpenoids, and fatty acid esters. In Physalis, fatty acid esters were predominant, followed by fatty acids and related compounds. UPLC/MS analysis of methanol extracts tentatively identified 16, 23, 21, 5, and 27 metabolites in Annona, Citrus, Hylocereus, Punica, and Physalis, respectively. Overall, methanol peel extracts, particularly from H. polyrhizus, C. sinensis, and P. granatum, exhibited strong larvicidal activity against Cx. pipiens, highlighting their potential as eco‐friendly alternatives for mosquito control.
L. al-Shuraym, L. A. Alkeridis, H. Alharbi et al.· Entomological Research· 0 citations
Environmental issues associated with the excessive use of chemical substances have received increasing attention globally, particularly regarding their effects on non-target/beneficial insects such as pollinators. To overcome such drawbacks, alternative control methods are being increasingly evaluated. A study was conducted to assess the effectiveness of two Indian biopesticidal isolates against the mustard aphid, Lipaphis erysimi, on rapeseed crops and to investigate their potential risks to the pollinator honeybee, Apis cerana. Laboratory bioassays showed that Beauveria bassiana AS-4220 was the most effective material against L. erysimi after 24 h (LC50 = 95.5 ppm); however, neem seed oil was the most toxic to A. cerana after the same time interval (LC50 = 185.4 ppm). The highest reduction in the aphid population under field conditions was observed with B. bassiana AS-4220 at 3 × 108 spores mL− 1 ten days after field treatment (71.9%), followed by B. bassiana AS-4220 at 2 × 108 spores mL−1 ten days after field treatment (70.7%). The highest PT (persistent toxicity index) and RPT (relative persistent toxicity) values were observed for B. bassiana at 3 × 108 spores mL− 1 (799.98 and 1.06, respectively). The benefit: cost ratio among the treatments was highest for B. bassiana at 3 × 108 spores mL− 1 (4.90:1). However, the highest honeybee mortality was observed following treatment with neem seed oil at 3 mL L− 1 and B. bassiana at 3 × 108 spores mL− 1 ten days of treatment (100%). No significant inhibition of acetylcholinesterase (AChE) activity was observed in honeybees 24 h after treatment. The study demonstrates that entomopathogenic fungi effectively control L. erysimi while posing some risk to A. cerana, particularly at higher concentrations, necessitating careful timing of application . Therefore, these treatments may be used to manage L. erysimi in rapeseed crops while minimizing effects on A. cerana bees, provided that application is scheduled during periods of low foraging activity.
Abhinandan Yadav, A. Devee, Ataur Rahman et al.· Scientific Reports· 0 citations
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