You might take a "wait and see" approach. The first year it struck my garden was horrible. It was EVERYWHERE! The second year---not-so-much. since then it has been hardly noticeable until late in the season when the foliage normally looks a little rough here because of our intense heat in July and August. I clean up all the previous year's foliage during the Winter before new growth in the Spring. I am sure this helps, too. I do not use spray. I got rid of about 20 plants that were the worst for it, too. Some cultivars are more susceptible than others and it is not worth keeping them around.