Lethal and sublethal effects of thiacloprid on survival, growth and reproduction of<i>Helicoverpa armigera</i>(Lepidoptera: Noctuidae)

Physiological Entomology

2022

The side effects of insecticides on non-target species are important to secure the intended effectiveness of pest management programs. The cotton aphid Aphis gossypii is a frequent problem in industrial greenhouse cultivation, and insecticide and parasitoids are often used for crop protection. Among insecticides, mixtures are playing increasing roles in pest management in greenhouse production system, as well as parasitoid use. The insecticide mixture thiacloprid + deltamethrin and the parasitoid wasp Aphidius colemani are the main agents used against the cotton aphid and are the focus of this study. Here, we report the effects of the thiacloprid + deltamethrin on A. gossypii and Aphidius colemani. The sublethal concentrations 2.80 mg ai/l (LC 10 ) and 7.28 mg ai/l (LC 30 ) compromised the demographic parameters of the aphid progeny and increased the development time at all juvenile stages. In addition, fecundity, longevity and population parameters (r, R 0 , and T) were signi cantly impaired by thiacloprid + deltamethrin, at both concentrations. The median lethal time estimate (LT 50 ) for Aphidius colemani was 18.73 h; the parasitoid mortality was signi cant up to 24 h after application, but decreased afterwards.Regardless, the parasitoid life table parameters were also compromised by insecticide exposure, similarly to the parasitoid population growth and parasitism e cacy. These results demonstrate the effect of the insecticide mixture against A. gossypii, as well as the increased risk of its adverse impacts on the parasitoid Aphidius colemani, which signals against their simultaneous application to control this pest species.

Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Thiacloprid + deltamethrin against the cotton aphid and the parasitoid wasp Aphidius colemani: From lethal to sublethal population effects

Physiological Entomology

2022

Section: Discussionmentioning

confidence: 99%

Thiacloprid + Deltamethrin Against the Cotton Aphid and the Parasitoid Wasp Aphidius Colemani: From Lethal to Sublethal Population Effects

et al. 2021

Preprint

The side effects of insecticides on non-target species are important to secure the intended effectiveness of pest management programs. The cotton aphid Aphis gossypii is a frequent problem in industrial greenhouse cultivation, and insecticide and parasitoids are often used for crop protection. Among insecticides, mixtures are playing increasing roles in pest management in greenhouse production system, as well as parasitoid use. The insecticide mixture thiacloprid + deltamethrin and the parasitoid wasp Aphidius colemani are the main agents used against the cotton aphid and are the focus of this study. Here, we report the effects of the thiacloprid + deltamethrin on A. gossypii and Aphidius colemani. The sublethal concentrations 2.80 mg ai/l (LC10) and 7.28 mg ai/l (LC30) compromised the demographic parameters of the aphid progeny and increased the development time at all juvenile stages. In addition, fecundity, longevity and population parameters (r, R0, and T) were significantly impaired by thiacloprid + deltamethrin, at both concentrations. The median lethal time estimate (LT50) for Aphidius colemani was 18.73 h; the parasitoid mortality was significant up to 24 h after application, but decreased afterwards. Regardless, the parasitoid life table parameters were also compromised by insecticide exposure, similarly to the parasitoid population growth and parasitism efficacy. These results demonstrate the effect of the insecticide mixture against A. gossypii, as well as the increased risk of its adverse impacts on the parasitoid Aphidius colemani, which signals against their simultaneous application to control this pest species.

Thiacloprid + Deltamethrin on the Life-Table Parameters of the Cotton Aphid, Aphis gossypii (Hemiptera: Aphididae), and the Parasitoid, Aphidius flaviventris (Hymenoptera: Aphelinidae)

Journal of Economic Entomology

et al. 2020

A combination of pesticides and biological control agents is frequently necessary to achieve successful pest management requiring the assessment of their compatibility for the intended purpose. Aphidius flaviventris Kurdjumov is one of the parasitoids of the cotton aphid Aphis gossypii Glover, whose susceptibility to pesticides was not yet investigated. Accordingly, we investigated the lethal and sublethal effects of the commonly utilized insecticide mixture thiacloprid + deltamethrin on the cotton aphid and its parasitoid wasp Aphidius flaviventris. The estimated LC50 for the aphid was 14.1 mg ai/l; the effects of sublethal exposure at LC10 (2.80 mg ai/l) and LC30 (7.28 mg ai/l) on the aphid life-table parameters led to significantly increase on the development time of third- and fourth-instar nymphs and preadult. Sublethal exposure to the insecticide mixture compromised aphid longevity, fecundity, and life-table parameters (r, R0, and T). Moreover, population growth and parasitism rate of the parasitoid were significantly compromised at both concentrations of the insecticide mixture under sublethal exposure. These results not only indicate the efficacy of thiacloprid + deltamethrin against the cotton aphid, but also raise concerns regarding its negative impacts on the parasitoid Aphidius flaviventris and caution against its use in pest management programs.