Antifeeding and Oviposition Deterrent Effect of Ludwigia spp. (Onagraceae) against Plutella xylostella (Lepidoptera: Plutellidae)

Abstract

Plants produce a wide variety of bioactive compounds with insecticidal properties, such as secondary metabolites capable of interfering with the nutrition and reproduction of pest species such as Plutella xylostella. Thus, the objective of this study was to evaluate the effects of aqueous and ethanolic extracts of Ludwigia spp. (Onagraceae) on the feeding and oviposition of P. xylostella. Choice bioassays were performed using aqueous and ethanolic extracts. The aqueous extract of L. tomentosa resulted in an approximately 81% reduction in larval feeding compared to that in the control, with an antifeedant index (AI) of 52%. The aqueous and ethanolic extract of L. nervosa acted by stimulating larval feeding. The oviposition was significantly reduced in the kale leaves treated with aqueous and ethanolic extracts of Ludwigia spp. The aqueous extracts promoted an average 90% reduction in oviposition when compared to that in the control, and an oviposition deterrent index (ODI) above 61% was classified as an oviposition deterrent. In addition, ethanolic extracts affected 81% of oviposition, with an ODI above 41%. Bioassays should be performed to clarify the use of aqueous and ethanolic extracts of L. nervosa as they acted as phagostimulants in the feeding tests and as deterrents in the oviposition tests. The phenolic compounds—flavonoids, condensed tannins, and alkaloids—were more abundant in L. nervosa, L. tomentosa, L. sericea, and L. longifolia. The extracts of L. longifolia and L. tomentosa showed the best results, interfering with the host choice for feeding and oviposition in P. xylostella and representing an alternative for the control of diamondback moths.

Aqueous botanical extracts, via different extraction methods, for control of the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae)

“…H. Hara (Onagraceae) demonstrated insecticidal potential against newly emerged larvae of P. xylostella, with mortalities ranging from 14-38%(Ferreira et al 2020).Recently researchers have shown that aqueous ethanolic extract made by leaf maceration and seed oil of Triadica sebifera (L.) (Euphorbiaceae), as well as their combinations, can be recommended as anti-food to reduce damage caused by P. xylostella, and safely for predators/parasitoids under eld conditions (Dolma and Reddy 2022). In the same sense, the aqueous botanical extract by maceration, at a concentration of 10% (w/v), of L. tomentosa, resulted in a reduction of approximately 81% in the feeding of P. xylostella larvae in relation to the control(Ferreira et al 2022).…”

Bioactivity of essential oils from three species of Mentha against Plutella xylostella (Lepidoptera: Plutellidae)

“…After determining the consumption of each leaf disk (treated and control), the feeding deterrence index (FDI) was calculated as follows: FDI = 100{(C -T) / (C + T)}, in which C and T (Isman 1993) refer to the areas consumed on the control and treated disks, respectively. Based on the FDI, the EO solutions were classi ed as phagodeterrent (positive values) or phagostimulant (negative values) (Ferreira et al, 2022).…”

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

“…An aqueous extract with a concentration (weight/volume) of 10%, conventional concentration, was obtained through the maceration technique and the addition of 10 g of the powdered plant material to 100 mL of distilled water by [11,19,23]. After manual stirring, the solution remained at rest for 24 h in a refrigerated environment (10 • C).…”