The diamondback moth (Plutella xylostella) is a major pest of broccoli crops in Colombia. To control P. xylostella, we evaluated the interaction of Beauveria bassiana Bb9205 and Metarhizium anisopliae Ma9236 with Heterorhabditis bacteriophora HNI0100 and its bacterial symbiont Photorhabdus luminescens HNI0100. We used antagonism and disk diffusion assays with fungal extracts to test the interaction between symbiotic bacterium and fungi. P. luminescens inhibited the growth of B. bassiana and M. anisopliae up to 40% by the secretion of secondary metabolites, whereas fungal extracts did not inhibit P. luminescens; this explains the in vivo interactions of these biological control agents. To test the interaction between fungi and nematodes, we first inoculated the fungi followed by the nematodes on different days (0, 2, 4, and 6). We identified the type of interaction using the formula by Nishimatsu and Jackson (J Econ Entomol 91:410–418, 1998) and established that on days 0, 2 and 4 there was an antagonistic interaction, while a synergistic interaction occurred on day 6. Therefore, the use of the interaction between H. bacteriophora HNI0100 with M. anisopliae Ma9236 and B. bassiana Bb9205 is an innovative alternative for the control of P. xylostella.

The European rabbit (Oryctolagus cuniculus) is one of the main invasive species in Chile, where it became naturalized ca. 150 years ago. Their high reproductive capacity, lack of specialist predators, and great adaptability favored the settlement of rabbits in diverse mainland and island ecosystems of the country. Recently, rabbits have become central players in semi-arid ecosystems, such as those represented in Las Chinchillas National Reserve in north-central Chile. We undertook to analyze the place and role of rabbits in the food web of that Reserve, based on a bibliographic review and long-term annual data gathered from 1987 until 2022 (36 years). Results showed that the network comprised 77 species, where 69% were primary producers (plants), 18% were mid-level consumers (herbivores), and 13% were top-level consumers (predators). The most connected species in the food web was the rabbit, which positively or negatively affected the species interacting with it. Predators such as Galictis cuja, Geranoaetus polyosoma, Leopardus colocolo, and Puma concolor, and the scavenger Vultur gryphus, could be negatively affected by an eventual decrease (natural or human-caused) in the rabbit population of the Reserve. To the contrary, primary producers such as Oxalis perdicaria, Plantago hispidula, Schizanthus parvulus, Senna cumminggi, and Tropaeolum azureum could be positively affected by an increase in their biomass in response to a decrease in rabbits, favoring native rodents. We consider that analyzing the rabbit-centered food web and its impacts on native interacting species allows a better understanding of the relevance of invasive species in the local community, providing conceptual tools for rabbit management.

Given the lack of knowledge in Cecropia mutisiana Mildbr phytochemical and pharmacological properties, the objective of this work was to determine the plant’s antioxidant and antimicrobial capabilities, taking into account its wide use by Colombian communities. For this study Rosmarinus officinalis Govaerts extracts were used as experimental standards for comparisons, since there are no studies devoted to Cecropia mutisiana Mildbr biological activities. Extraction was performed by frozen plant grinding obtaining extracts of different polarity (petroleum ether, ethyl acetate, dichloromethane, and ethanol). To identify Cecropia mutisiana Mildbr functional groups and main compounds preliminar phytochemical analysis was run. Likewise, antioxidant capacity for both plants was determined by analytical methods including DPPH, ABTS, and ORAC; followed by phenol quantification correlation by Folin Cicocalteu reagent. Last, its antimicrobial capacity was established by the Kirby-Bauer test. Cecropia mutisiana Mildbr ethanol extract had the highest antioxidant capacity expressed as IC50 (165.47 ± 3.0 ppm), as well as the dichloromethane Rosmarinus officinalis Govaerts extract (272.63 ± 4.9 ppm), without any correlation with total phenols. Additionally, antimicrobial activity was observed for Cecropia mutisiana Mildbr in the ethyl acetate extract and for Rosmarinus officinalis in the ethanol extract. In conclusion, regarding both plant comparison Cecropia mutisiana Mildbr ethanol extract had the highest antioxidant capability, whereas Rosmarinus officinalis Govaerts ethanol extract had the greatest antimicrobial activity.