Toxic effects of Acmella oleracea and Carlina acaulis extracts on Aculops lycopersici, Tetranychus urticae and their predators
2026 - Volume: 66 Issue: Suppl pages: 87
https://doi.org/10.24349/sbg6-e3oe
ICA 2026 - XVII International Congress of Acarology, 20-24 July 2026, Montpellier
Keywords
Biochemicals
Eriophyoid mites
Tetranychid mites
Phytoseiid mites
Side effects
Abstract
This study aimed to evaluate the biocidal activity of N-alkylamide-enriched extract from Acmella oleracea and carlina oxide from Carlina acaulis, against two pest mites, Aculops lycopersici and Tetranychus urticae, and to evaluate their side effects on three phytoseiid species. The extracts were applied on adults of A. lycopersici and on different developmental stages of T. urticae (eggs, nymphs, and adult females), using six concentrations (0, 320, 640, 1280, 2500, 5000 µL L?¹). The side effects on phytoseiids have been evaluated on Typhlodromus exhilaratus (eggs and adult females) at 1280 and 5000 µL L?¹ of Acmella extract and at 1280 µL L?¹ of carlina oxide; on Neoseiulus californicus eggs at 1250 µL L?¹ and adult females at 5000 µL L?¹ of carlina oxide, and on Amblydromalus limonicus (eggs and adult females at 5000 µL L?¹of Acmella extract). Each test was conducted using five mobile mites per replicate while for T. urticae eggs, 10 eggs were used per replicate; each test included 10 replicates. Both extracts showed high toxic against A. lycopersici. Probit analysis estimated LC50 values of 205.32 µL L?¹ for carlina oxide and 253.79 µL L?¹ for Acmella extract. On T. urticae females, LC50 values were 1158 µL L?¹ for carlina oxide and 284.94 µL L?¹ for the Acmella extract. Carlina oxide showed less toxic on nymphs (LC50 1825 µL L?¹), but it resulted very toxic on eggs (434.3 µL L?¹). On the other hand, Acmella extract showed more toxic for T. urticae nymphs (LC50 569.60 µL L?¹), but the ovicide effect was less evident (2584.81 µL L?¹). Side effects on phytoseiids were species-specific. On T. exhilaratus females, carlina oxide caused 39.13% of mortality at 1280 µL L?¹, whereas the Acmella extract induced mortality ranging from 18.75% to 58.5% at 1280 and 5000 µL L?¹ respectively. Carlina oxide also reduced egg hatching of T. exhilaratus by 50%, while Acmella extract showed harmless. On N. californicus females, carlina oxide did not cause mortality but showed a strong repellent effect. Conversely, Acmella extract caused 96% mortality on adult females of A. limonicus. Both extracts showed harmless on eggs of N. californicus and A. limonicus. Overall, both extracts proved to be highly toxic to phytophagous mites, with variable negative impact on predatory species. These results highlight their potential as botanical acaricides, but also the need for careful evaluation before their integration into integrated pest management programmes.
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