Abstract

RUIZ-SANCHEZ, Esaú et al. Survivorship and development of immature Harmonia axyridis Pallas (Coleoptera: coccinellidae) exposed to diflubenzuron. Agrociencia [online]. 2010, vol.44, n.3, pp.373-379. ISSN 2521-9766.

The multicolored Asian lady beetle, Harmonia axyridis Pallas (Coleoptera: Coccinelliadae), is a voracious predator of soft-bodied insects that has been widely used for biological control. In this work, we examined the effects of dilflubenzuron, an insect growth regulator (IGR), on a young population of H. axyridis under laboratory conditions in order to evaluate the risk of using this IGR in integrated pest management programs. Larval and pupal stages of H. axyridis were dipped 3 s in diflubenzuron dilutions (50, 100 or 200 mg L^-1) or pure distilled water (control). The percentage of survival and the number of days from immature stage treated to adult emergence were evaluated. The negative effects were related to the developmental stages of H. axyridis and the concentration of diflubenzuron used. All concentrations caused significant effects (p<0.05) on survival when first and second-instar larvae were treated. When third-instar larvae were treated, only the highest concentration caused a significant decrease on H. axyridis survival. No significant effects on survival were found when forth-instar larvae and pupae were treated. Developmental time (days) of H. axyridis from immature stage treated to adult emergence increased significantly when first and second-instar larvae were treated with 200 mg L^-1 of diflubenzuron. Based on these results, the use of diflubenzuron might represent a risk for the population of H. axyridis in integrated pest management programs that combine the use of this IGR and predator in pest management strategies.

Keywords : H. axyridis; diflubenzuron; insect growth regulator; predator.

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