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Tuta absoluta, one of the most damaging pests of tomato crops and other solanaceous plants, has been extensively managed by the use of synthetic pesticides. Unfortunately, the reliance on chemicals has negatively affected human health, biodiversity, and the environment. Therefore, the development of eco-friendly alternatives is highly encouraged to replace hazardous chemical pesticides. Inhibitory cystine knot (ICK) peptides have a leading future as they present a narrow spectrum activity, and remarkable stability, making them promising bio-insecticide modalities against pests of crops of economic importance. In this study, the impact of Pea albumin 1-b (PA1b), a plant ICK peptide extracted from seeds of peas (Pisum sativum, Fabaceae) was investigated through foliar application to be delivered to 2nd instar larvae of T. absoluta. However, due to the failure of delivery upon foliar application, microinjections of the peptide into 3rd instar larvae were performed to assess the insecticidal activity of PA1b when being into the body cavity of the larvae. Toxicity bioassays were conducted in Petri dishes in a developed experimental arena that allowed us to easily survey the status of the larva and the leaf for up to 18 days. Our study showed that PA1b has a significant toxic effect against T. absoluta when delivered through injection. Further studies must be conducted to optimize the administration of PA1b into the larvae of T. absoluta, investigate the binding sites of the peptide in this pest, and ascertain the insecticidal capacity of such a peptide at an agricultural-relevant scale. [ABSTRACT FROM AUTHOR]

Aphids are recognized as a major threat to economically important crops. Their control is predominantly based on synthetic insecticides that are detrimental to human health and the environment. Botanical pesticides based on essential oils (EOs) are a promising alternative. In this study, the entomotoxicity of green anise and fennel EO fumigation was tested on the potato aphid Macrosiphum euphorbiae. Three different settings of increasing scale were considered (leaflet, whole plant and greenhouse) to appraise the consistency of EO impact from controlled laboratory to greenhouse production conditions. LC50 values for green anise and fennel were 6.6 μl L−1air and 12.2 μl L−1air, respectively, based on dose-response curves in leaflet experiments but fennel EO induced phytotoxicity. EO efficiency was confirmed at the whole-plant scale. In the greenhouse experiment, fennel EO exhibited greater efficiency than at the laboratory scale equaling green anise EO efficiency but both EOs showed delayed phytotoxicity, illustrating the importance of long-term monitoring. The present study revealed the ability of both EOs to control M. euphorbiae populations under greenhouse conditions and hinted at the importance of assessing EO efficiency in realistic agronomic conditions (e.g., under the fluctuating environmental conditions usually occurring in greenhouses). [ABSTRACT FROM AUTHOR]