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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]

The pea aphid Acyrthosiphon pisum Harris is a major insect pest of Fabaceae crops causing significant damage and economic losses. Its management is a real challenge and the use of plant essential oils (EOs) as biorepellents is a serious alternative to chemical pesticides. Here, we conducted for the first time an in-depth study on the effects of forty plant EOs and their chemical compounds on A. pisum. Using choice bioassays, we reveal the strong repellency of Chinese cinnamon, peppermint, anise, basil, spearmint, and dill oils. Analysis of their chemical composition shows that their respective high contents of trans-cinnamaldehyde, trans-anethole, menthol + menthone, estragole and carvone could be responsible for their high repellency. An additional economic analysis underlines that peppermint EO is the most available and the cheapest. Our data show that peppermint EO with menthol and menthone as major compounds seems to be the most promising EO as biorepellent against the pea aphid. Overall, the repellent activity of peppermint EO may provide a new way to control A. pisum in the future, which may lead to effective strategies for controlling these sucking pests. • Forty plant essential oils (EOs) were tested as biorepellent against the pea aphid. • Peppermint with high contents of menthol + menthone is among the most repellent. • With its high availability and low price, it has great potential as biorepellent. [ABSTRACT FROM AUTHOR]