Non-target Effects Of Dalaca pallens Blanchard Control Examined Through Principal Response Curves: A Guild Approach In Southern Chile

The non-target effects of biological control are a complex matter requiring a multi-approach analysis. A fungal biopesticide is under research to control the larval stages of the ghost moth Dalaca pallens Blanchard (Lepidoptera: Hepialidae) in southern Chile. A field experiment was conducted to compare the effects of the biological control agent Beauveria bassiana (Balsamo) Vuillemin (1012 spores ha-1) and the insecticide lambda-cyhalothrin (7.5 g active ingredient ha-1) on non-target invertebrate species belonging to different guilds. The soil invertebrates were collected by using pitfall trapping and soil coring before and after spraying the biocontrol agent or the insecticide. Caught individuals were assigned to predator, herbivore or decomposer guilds and then a relatively new multivariate technique called principal response curves (PRC) was adopted to track the potential treatment effects over time in the abundance or activity of the non-target guilds. The products targeting D. pallens caused different effects on guilds: lambda-cyhalothrin decreased the activity-density of the predator guild but not herbivore or decomposer guilds, while the biological control agent caused no reduction in the activity-density of the three examined guilds. The negative effects of the insecticide were present from 1 to 60 days after treatment. Los efectos no deseados del control biológico son una materia compleja que requiere un análisis desde enfoques múltiples. Se está investigando un bioplaguicida fúngico para controlar los estados larvarios de la polilla Dalaca pallens Blanchard (Lepidoptera: Hepialidae) en el sur de Chile. Se realizó un experimento de campo para comparar los efectos del agente de control biológico Beauveria bassiana (Balsamo) Vuillemin (1012 esporas ha-1) y el insecticida lambda-cihalotrina (7,5 g i.a. ha-1) en invertebrados distintos a la plaga que pertenecen a diversos gremios. Los invertebrados se colectaron mediante trampas de caída y por extracción de cilindros de suelo antes y después de la aplicación del agente de control biológico o del insecticida. Los individuos capturados se clasificaron como depredadores, herbívoros, y descomponedores, y luego se usó una técnica estadística multivariada llamada curvas de respuesta principal (PRC) para evaluar los efectos potenciales de los tratamientos a través del tiempo, en la abundancia o actividad de los gremios. Los productos usados contra D. pallens produjeron efectos diferentes en los gremios: el