When applied at its recommended highest concentrations, azoxystrobin residues, like pest control residue, will continue to work as a preventative and curative control of fungal diseases in turf grass and crops for 28 days. Read the label instructions on your azoxystrobin to find out how long the azoxystrobin active ingredients will work to protect your lawn and plants from diseases. The time it takes azoxystrobin to work on plant roots depends on the amount of disease present in your plants – as with pesticides, the time it takes to work varies.