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Are mycorrhizae compatible with chemical pesticides?

It depends on the nature of the chemical used. Some general pesticides and most systemic fungicides can be harmful to mycorrhizae. In general, we recommend applying them separately and to avoid mixing pesticides and mycorrhizae together in the same tank. Drench fungicide applications should be avoided unless the product is indicated as safe for mycorrhizal fungi.

Even then we would suggest that it only be applied at least two weeks prior or four weeks after mycorrhizae inoculation. The more you wait to apply compatible fungicide after sowing, the better mycorrhizae will perform. Foliar sprays of fungicide (except systemic ones) have little or no effect on mycorrhizae performance. If you have any doubt or questions about pesticides application alongside mycorrhizae, or specific product compatibility inquiries, please contact

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