A new technique for determining the sublethal toxicity of pesticides to the vesicular-arbuscular mycorrhizal fungus Glomus intraradices

Sublethal toxicity of selected reference pesticides and solvents to the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus intraradices growing on root inducing transferred DNA (Ri T-DNA)-transformed roots of Daucus carota was determined using a new bioassay technique. Determinations were made on the concentration causing 50% inhibition of growth and development (IC50) to G. intraradices of acetone, methanol, benomyl, chlorothalonil, copper sulfate, dimethoate, glyphosate, and aminomethylphosphonic acid. Effects of these test materials on carrot roots and colonization by G. intraradices were also evaluated. The potential for using G. intraradices as an indicator species and the new technique as a standard test to determine the toxicity of pesticides on VAM fungi for the evaluation of ecosystem impact is discussed