 It's best. If not, you've got to be on the lookout. They can wipe out your potato crop. They can take several leaves. They're leaf eaters, so they will just shred, make doilies out of your leaves, and you're not feeding the plant. You're not getting your potatoes and your other vegetables. So you've got to keep on them. The nice thing with working with potatoes are underground. So your leaves, you're just treating the leaves. So you can use different insecticides. Look in your local store. Find something.