RESUMO
Persicaria acuminata (Polygonaceae) is a perennial herb that grows in the central area of Argentina and it is commonly used by native populations to heal infected wounds and other conditions related to fungal infections. In this article, we explored the in vitro antifungal activity of its ethyl acetate extract against a panel of three fruit phytopathogenic fungi including: Penicillium digitatum, P. italicum, and Monilinia fructicola. The sesquiterpenes isolated from the extract were also evaluated against these strains, demonstrating that the dialdehyde polygodial was the responsible for this activity. In order to encourage the use of the extract rather than the pure compound, we displayed ex vivo assays using fresh oranges and peaches inoculated with P. digitatum and M. fructicola, respectively, and subsequently treated by immersion with an extract solution of 250 and 62.5 µg/mL, respectively. There were no statistically significant differences between the treatments with commercial fungicides and the extract over the control of both fruit rots. The concentration of the active compound present in the extract used on fruit experiments was determined by Gas Chromatography-Mass Spectroscopy. Finally, cytotoxicity evaluation against Huh7 cells showed that P. acuminata extract was less cytotoxic than the commercial fungicides at the assayed concentrations. After these findings we could conclude that a chemically characterized extract of P. acuminata should be further developed to treat fungal diseases in fruits from an agro-ecological model.
RESUMO
BACKGROUND: The Spodoptera cosmioides (Walker, 1858) population has increased in Bacillus thuringiensis Berliner (Bt) soybean crops in Argentina. As there are no registered products for its control, the recommended insecticides for S. frugiperda are used. The aim of this study was therefore to determine the lethal concentration (LC) of chlorantraniliprole and its sublethal effects on the biological and reproductive functions of S. cosmioides, an emerging soybean pest in Argentina. RESULTS: An ingestion toxicity bioassay showed that chlorantraniliprole was active against larvae of the second instar, and after 48 h of exposure LC50 was 0.054 µg mL-1 H2 O. In the study of sublethal effect, chlorantraniliprole induced changes in the life cycle of exposed S. cosmioides, which required more time to complete all stages of development (larval, pupal and adult stages). Pupal weight was also higher in larvae exposed to sublethal concentrations of chlorantraniliprole. Adult fecundity was decreased: the number of eggs laid by each adult female moth, as compared with control females, was two (LC15 ) and eight (LC30 ) times lower. CONCLUSION: These results indicate that chlorantraniliprole has toxicity against S. cosmioides larvae. Sublethal effects on the biological and reproductive performance of this species can help optimize integrated pest management programs. © 2018 Society of Chemical Industry.