1 September 2020

INNOLIVAR project for the control of the olive fruit fly: soil persistence of the bioinsecticide formulations


Efficacy is certainly the main factor to be considered when marketing a plant protection product, but not the only one. The persistence in the different elements of the environment (soil, plant, surface water and groundwater. Etc.) is also an important factor: it determines the environmental impact of the product and, sometimes, can influence its effectiveness. Determining the persistence of products in the soil is especially important in the case of those that are directed at pathogens that develop part of their life cycle in the soil, as is the case of the olive fruit fly, whose pupae grow underground.

This is why in the INNOLIVAR project, in which Futureco Bioscience is developing a bioinsecticide product based on the entomopathogenic fungus Metarhizium brunneum strain EAMb 09/01-Su to control the olive fruit fly, researchers from the Department of Molecular Biology have tested the persistence of our formulas in the soil, through a real-time quantitative PCR method.

The results, detailed in the Ecoletter 29, have validated the detection methodology and, in addition, show that the fungus formulated both in wettable powder, and in dispersible oil can persist in the soil for more than 200 days, with high levels. Curiously, the microsclerotia formulation has registered a more variable persistence dynamics in the soil: a great increase in the levels of M. brunneum (up to 7 orders of magnitude) that correlates with the arrival of spring and the consequent rise in temperatures. This dynamic is consistent with the biological function of microsclerotia, forms of resistance composed of condensed hyphae that develop and sporulate only when environmental conditions are favorable.