Assessment of acute toxicity tests and rhizotron experiments to characterize lethal and sublethal control of soil-based pests

Autor: Mario Schumann, Stefan Vidal, Annika Agatz, Colin D. Brown, Bryan Wade French
Rok vydání: 2018
Předmět:
Zdroj: Pest Management Science. 74:2450-2459
ISSN: 1526-498X
DOI: 10.1002/ps.4922
Popis: BACKGROUND: Characterising lethal and sub-lethal control of soil-based pests with plant protection products is particularly challenging due to the complex and dynamic interplay of the system components. Here we present two types of studies: acute toxcity experiments (homogenous exposure of individuals in soil) and rhizotron experiments (heterogeneous exposure of individuals in soil) to investigate their ability of strengthening the understanding of driving mechanisms of effectivness of the plant protection product. Experiments were conducted with larvae of the western corn rootworm Diabrotica virgifera virgifera LeConte and three pesticide active ingredients (clothianidin (neonicotinoid), chlorpyrifos (organophosphate), and tefluthrin (pyrethroid). RESULTS: The order of compound concentrations needed to invoke a specific effect intensity (EC50 values) within the acute toxicity tests was chlorpyrifos > tefluthrin > clothianidin. This order changed for the rhizotron experiments because application type, fate and transport of the compounds in the soil profile and sub-lethal effects on larvae also influence their effectiveness in controlling larval feeding on corn roots. CONCLUSION: Beyond the pure measurement of efficacy through observing relative changes in plant injury to control plants, the tests generate mechanistic understanding for drivers of efficacy apart from acute toxicity. The experiments have the potential to enhance efficacy testing and product development and might be useful tools for assessing resistance development in the future.
Databáze: OpenAIRE
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