Diversidad y control biológico de insectos - CyberTesis UACh ...

Scarabaeidae) have shown that the fungus has the potential to infect and kill non target
species, at least in the laboratory (Devotto et al., 2003).
The studies mentioned above were conducted on selected beneficial species, but less work
has been done to compare the effects of D. pallens control strategies at the community
level. This knowledge and adequate assessment of the ecological risks of B. bassiana are
needed before scaling to extensive use, to prevent unintended adverse effects on the
grassland ecosystem functioning, including natural pest control. Regardless of the habitat or
ecosystem, arthropods contribute well over half of the metazoan species (Dennis, 2003),
playing different roles, including herbivore regulation, nutrient cycling and other ecosystem
processes. In relatively simple systems such as grasslands, arthropods even have a higher
preponderance.
The aim of this study was to compare the effects of conventional and biological control of
D. pallens on the grassland arthropod community of South Chile. We designed two
experiments to test the hypothesis that B. bassiana biopesticide would be less disruptive to
the ground-dwelling arthropofauna than the insecticide lambda-cyhalothrin.
Materials And Methods.
Sites and environmental data.
Two trials were conducted: one in winter and one in spring. The winter trial was conducted
on a farmer’s field near Osorno, Chile (40º35’ S, 73°10' W), from July to September 2003.
Plant cover was composed of hybrid ryegrass (Lolium perenne x Lolium multiflorum; 80-90
%) and broad-leaf species, including Plantago spp and Cyperaceae (