Q: Last summer my nasturtium leaves were often covered with aphids. Because I prefer not to use insecticides, I knocked them off with a hose. Is there anything else I can do? -- Barbara Arnett, Chicago A: Keep knocking the aphids off with the hose, but also try to attract more beneficial insects to your landscape. Lady beetles, also known as ladybugs, are an important natural enemy. Both their larvae and adults are hungry feeders of aphids, as well as mealybugs, mites and other common bugs. When aphids are present, lady beetles will often find them on their own. But you can also encourage them to visit your yard by planting flowering annuals and perennials that are especially attractive to them. Good choices include morning glory, angelica, goldenrod and yarrow. Lady beetles will remain as long as there are aphids or other insects they like to eat. Make your yard hospitable to lady beetles by continuing to avoid using pesticides. Insecticides kill beneficial insects at the same time they are controlling pests.
Robin Carlson/Chicago Botanic Garden