Insecticidal effects of Vernonanthura nebularum against two economically important pest insects

Abstract

Vernonanthura nebularum (Cabrera) H. Rob. (Asteraceae), an endemic species from the north of Argentina, is a rich source of elephantopus-type sesquiterpene lactones. These compounds have proved to be promising antiparasitic agents, but there is no report about their action against pest insects. In this work we studied for the first time the antifeedant and toxic effects of V. nebularum natural products against the fall army warm Spodoptera frugiperda Smith and the oviposition deterrent activity against the fruit fly Ceratitis capitata Wiedemann. As a result, we found that extracts, fractions composed of sesquiterpene lactones and pure sesquiterpene lactones altered larval feeding behavior in the food choice test. Nutritional parameters of S . frugiperda larvae were also affected. Fraction II (300 μg/g of diet.), containing compounds 1 , 2 and 3 , was the most toxic substance with 80% pupal mortality and wing malformations in adults. In oviposition deterrent experiments against Ceratitis capitata , we observed a moderate effect at 30 μg/cm 2 of the test compound. The most active substances were the methanolic extract, dichloromethane subextract and lactone 2 . According to our results, V. nebularum natural products could be used for maximizing the effectiveness and specificity in future insecticide design with specific or multiple target sites, while ensuring the economic and ecological sustainability, in addition to combat the increasing resistance rates developed by synthetic pesticides.

Biological activity of Dittrichia viscosa (L.) Greuter extracts against adult Sitophilus granarius (L.) (Coleoptera, Curculionidae) and identification of active compounds

“…Plant extracts exerted negligible effects on nutritional parameters of adult weevils except for the highest dose of water extract that caused a significant reduction of food intake (RCR) and relative growth rate (RGR) when compared to control. Since no ingestion toxicity was observed this alteration in nutritional parameters indicates the presence of antifeedant constituents in the water extract (rather than post-ingestion toxicants) which more likely act on the gustatory organs of the mouthparts 38 . However, chemical analysis of water extract is needed to support or refute this hypothesis, as well as for better understanding the variability registered with this extract for the other nutritional indexes.…”

Suppressive Impact of 6-Benzyladenine, A Plant Growth Regulator, on the Adult Performance and Reproductive Potential of Galleria mellonella L. (Lepidoptera: Pyralidae)

“…Topical application of Farnesol onto 5 th instar nymphs of the red cotton stainer Dysdercus koenigii led to the metamorphosis of adults with malformed wings (Kumar and Gupta, 2017). Sosa et al (2019) observed serious wing malformations in adults of S. frugiperda after larval treatments with some Sesquiterpene lactone compounds. Feeding of S. littoralis 2 nd instar larvae on plant leaves previously dipped in Nano-chitosansolution led to the production of deformed adult moths (Marouf, 2020).…”

Impairing Effectiveness of Nerolidol, a Sesquiterpene Compound, on Adult Performance and Reproductive Potential of Egyptian Cotton Leafworm, Spodoptera littoralis (Lepidoptera: Noctuidae).

“…Larval treatment with Pogostone (isolated as the main constituent of essential oil from Pogostemon cablin) resulted in some deformities in adult moths of S. litura and the beet armyworm Spodoptera exigua (Huang et al, 2014). Fraction II (300lg/g of diet) from Vernonanthura nebularum natural products was found the most active substance causing wing malformations in adults of the fall armyworm Spodoptera frugiperda (Sosa et al, 2019).…”