Tradescantia pallida L. (Commelinaceae) influences the activity of oviposition and feeding of Plutella xylostella (Lepidoptera: Plutellidae)

Abstract

Diamondback moth represents one of the major Brassicaceae plagues and the main current control method relies on the agrotoxins use. The search for alternative phytosanitary control methods demonstrates that the vegetal extracts have broadly studied and now represent a relevant option to control insects-plagues in small cultivation areas. Was evaluated the effect of the aqueous extract Tradescantia pallida 10% in oviposition and the feeding preference of Plutella xylostella, in laboratory conditions. That plant does not present herbivory reports, which raises the hypothesis of representing an efficient control alternative. P. xylostella couples introduced in experimentation cages for 10 days, to assess the activity of oviposition, being exposed to the botanic extract in the feeding and the oviposition substrate, with the eggs average number per day and fertility being assessed. To assess feeding, two tests developed: free choice and no choice of food source during 48 hours of evaluation. The results indicate that the aqueous T. pallida extract changes the oviposition activity of P. xylostella, reducing the average number of eggs per day and the fertility. It was also possible to observe the non-preference, regarding feeding, for substrates that were treated with the extract. The results observed in the study can contribute to amplify the small producers decision-making processes and the involved sectors regarding the choice of supplies that respect environmental and human health.

Tradescantia pallida (Commelinaceae) Promotes Reductions in Plutella xylostella (Lepidoptera: Plutellidae) Populations

“…Thus, these flavonoids may be directly related to changes in fecundity and fertility of P. xylostella, especially in the case of ETPI, reinforcing the hypothesis of a synergy between compounds. In contrast, as observed by Rocha et al [26] tannins function as a phagodeterrent, causing insect death or several sublethal effects throughout the insect life cycle [13,19,34].…”

“…The chemical composition evaluation of the extract performed by Rocha et al [26], indicated the presence of phenolic compounds and flavonoids, such as rutin, luteolin, and apigenin, in addition to anthocyanins and tannins. Of these, rutin is a flavonoid known to have an important role in plant protection against lepidopterans, demonstrating lethal and/or antinutritional effects during the larval stage [27,28].…”

Efeito de extratos aquosos de Serjania spp. sobre a oviposição de Plutella xylostella L. (Lepidoptera: Plutellidae)

“…A fertilidade e viabilidade dos ovos foram reduzidas, principalmente, utilizando extratos na concentração 10%, pois maiores concentrações garantem maior vulnerabilidade de ovos aos compostos bioativo e podem afetar o desenvolvimento embrionário e a viabilidade dos ovos (Matharu & Mehta, 2017;Sangha et al, 2017;Rocha et al, 2021). O efeito dissuasor ocorreu em todos os tratamentos, independentemente do método utilizado (sem chance ou com chance), entretanto, assim como nas demais características avaliadas, os maiores valores de IDO foram resultantes da maior concentração utilizada (10%), em quase todos os tratamentos, pois a medida que a concentração aumenta espera-se a extração de mais substancias bioativas do material vegetal que podem contribuir para o aumento do efeito dissuasor (Torres et al, 2001;Silva et al, 2019).…”