Publications by authors named "Marcela-Ines Schneider"
Article Synopsis
- Compatibility studies of insecticides often ignore long-term effects on natural enemies like parasites, focusing mostly on short-term lethal impacts.
- In a study of different insecticides on the pupae of the parasitoid Diaeretiella rapae, imidacloprid showed significant harm, reducing adult emergence, while spirotetramat and its mixtures only affected the parasitoid at higher doses.
- The findings suggest that imidacloprid is the most toxic to D. rapae, indicating that its use in pest management should be avoided to protect this potential biological control agent.
Article Synopsis
- The study examined the effects of two biorational insecticides, azadirachtin and pyriproxyfen, compared to a neonicotinoid insecticide, acetamiprid, on the Neotropical strain of Eretmocerus mundus.
- All three insecticides reduced adult emergence and survival, with azadirachtin being the most toxic at its highest recommended concentration.
- Sublethal effects, such as reproductive capacity, sex ratio, and longevity, were observed, particularly with pyriproxyfen negatively impacting female reproductive capacity in survivors.
Article Synopsis
- The study investigates the toxicity of a new insecticide, spirotetramat, on a specific strain of Eretmocerus mundus, comparing its effects to those of the conventional pesticide cypermethrin.
- Results show that spirotetramat is less harmful to both pupae and adult stages of the parasitoid compared to cypermethrin, which is known to be highly toxic to natural enemies.
- The insecticide spirotetramat negatively impacted the longevity and survival of the first progeny and reduced overall demographic parameters, highlighting the importance of evaluating pesticides' effects on beneficial organisms in agriculture.
Pesticides can be toxic to nontarget organisms including the natural enemies of agricultural pests, thus reducing the biodiversity of agroecosystems. The lethal and sublethal effects of four insecticides with different modes of action-pyriproxyfen, teflubenzuron, acetamiprid, and cypermethrin-were evaluated on pupae and adults of Eriopis connexa, an effective predator in horticultural crops. Pupal survival was reduced by pyriproxyfen (26 %) and cypermethrin (41 %).
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- * The study found that acetamiprid significantly reduces egg hatching (34 to 100% reduction) and disrupts early embryonic development across all tested concentrations.
- * Larval stages of E. connexa showed high susceptibility to acetamiprid, with larval survival dropping to 100% at low doses, and female reproduction also suffered, indicating that this insecticide could undermine integrated pest management strategies.
The long-term effects of methoxyfenozide on the longevity and reproductive processes of beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), adults were assessed after exposure by ingestion. Methoxyfenozide significantly reduced adult male longevity compared with females by 1.1 and 1.
View Article and Find Full Text PDFThe toxicity and sublethal effects of methoxyfenozide were evaluated in third instars of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), that fed on contaminated semisynthetic diet. The LC50 value was estimated at 0.23 mg of active ingredient (AI) /kg diet (range, 95% CI: 0.
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- Adult longevity in Spodoptera littoralis was reduced by both azadirachtin and methoxyfenozide, but no differences between sexes were noted, and both insecticides significantly impacted fecundity and fertility, particularly azadirachtin in a dose-dependent manner.
- The study found that the method of exposure affected results, with ingestion leading to fewer eggs laid compared to topical application.
- Azadirachtin also demonstrated a deterrent effect on egg-laying on pepper plants, but after extended observation, the number of eggs was not significantly different from the control group, indicating complex interactions with pest populations in treated crops.*
Article Synopsis
- - Chrysoperla externa, a beneficial predator in agriculture, was tested for sensitivity to various pesticides (cypermethrin, endosulfan, methoxyfenozide, and spinosad) during its immature stages, focusing on development time, survival rates, and reproductive outcomes.
- - While conventional insecticides (endosulfan and cypermethrin) caused high mortality rates in larval stages, biorational insecticides (spinosad and methoxyfenozide) showed less immediate and intense effects, indicating they may be safer for this beneficial predator.
- - Overall, the study highlights that biorational insecticides support the conservation of Chrysoperla externa by minimizing negative long-term effects on its
Susceptibility to methoxyfenozide of Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) larvae was determined through exposure of neonate and fourth instars to dipped and sprayed pepper, Capsicum annum L., leaves. Methoxyfenozide and spinosad were tested against adults of this noctuid by oral, residual, and topical application.
View Article and Find Full Text PDFThe toxicity of two biorational insecticides, spinosad (Tracer) and methoxyfenozide (RH-2485), was tested against eggs, larvae, and pupae of the noctuid Spodoptera littoralis (Boisduval). In the first experiment, filter paper circles containing egg masses of two different age classes, young (<24 h old) and old (24-48 h old), were dipped in different concentrations of each insecticide diluted in either water or acetone. No ovicidal activity was recorded when insecticides were diluted in water.
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- The study assessed the effects of seven modern insecticides on the lepidopteran parasitoid Hyposoter didymator, focusing on its susceptibility and various life parameters.
- At recommended field doses, methoxyfenozide and tebufenozide were safe, while diflubenzuron showed moderate toxicity, and azadirachtin, pyriproxyfen, and spinosad were very toxic, severely affecting the parasitoid's survival and reproduction.
- The research also evaluated the compounds' absorption and retention in H. didymator, finding that diflubenzuron had the highest absorption, indicating the need for careful evaluation of using certain insecticides in pest management programs involving this parasitoid.