When healthy and well cared for, hostas are a colorful addition to any shady garden. However, if they begin to look discolored or the leaves seem to be wilting away, spider mites may have moved in to your hosta bed for a long summer’s snack. To get rid of spider mites on hostas you’ll need to start with simple remedies, and if these don't work you can escalate the fight.
Blast the hosta with a heavy stream of water, working to spray the underside of leaves as well, to throw the mites off the hosta plant. Spray the plant like this every two to three days for a month as a first resort to see if you can drive the spider mites away.
Collect from your yard or purchase from a garden center ladybugs, also called ladybeetles, which are a natural predator of the mites, if the spraying isn’t working. Place the insects directly onto your hostas in a known spider mite area and leave them to eat all they want. If these natural methods don't work, go to the next step.
Apply a miticide to the hostas following the directions on the packaging for application method, dose, and frequency.
Trim away badly damaged leaves by cutting them off the plant as close to the ground as you can once you have gotten rid of the spider mites. Discard the leaves rather than composting them as they may contain spider mite eggs.
Watch any of your other plants which are near the hostas for signs of spider mites and treat them in the same manner as soon as possible.