The label will provide specific instructions. You must have separate sprayer equipment for herbicides and insecticides. Herbicide residues in a sprayer used to apply insecticides or fungicides may damage plants. Mix only enough of a pesticide to complete the job. Mixing exposes the applicator to the most concentrated form of the pesticide.
Special care is required.
Carefully measure concentrates with measuring spoons or cups reserved and labeled for that use only. No chemicals should be mixed together unless the label says they are specifically compatible. If more pesticide is mixed than is needed, it should be applied to plants that are on the label. Never pour a pesticide down the drain or storm sewer. Rinse the sprayer with fresh water, applying the rinse water to plants that are listed on the label.