Like me, you may be growing milkweed in your garden in the hopes of attracting beautiful monarch butterflies. If so, you have probably noticed numerous orange and black bugs on the plants in the past few weeks.
Often mistaken for boxelder bugs, these are likely large milkweed bugs or Oncopeltus fasciatus. They appear in groups and in all stages of growth from very small nymphs without wings to adult insects as large as 3/4 inch. They are mostly orange with black horizontal bands across the middle of their bodies and at the end of their wings. You will find them on stems, leaves and especially the milkweed seed pods.
Milkweed bugs puncture and feed on the seed pods, as well as the stems and leaves. They prefer common milkweed over other varieties of milkweed. I have several different types of milkweed growing together in my garden, and I only find this insect on the common type. Despite the number of insects often present, they do not harm the plant and do little damage. They also cause no harm to other insects and can be on the plant at the same time as monarch butterflies. They will not drive the butterflies away.
Often, just leaving them alone is the best course of action as the insect is present for only a short period of time at the end of the growing season. For those gardeners that do not like the appearance of the milkweed bug, they can be removed and squashed or placed in soapy water. An insecticidal soap, used as directed, is effective and safe as well. Removal and disposal of milkweed stalks in fall will discourage overwintering of the insect.
Fortunately, this is one bug in the garden that you don’t need to worry about!
Darlie Simerson is a University of Illinois Extension master gardener for Kane County. The “Learning to Grow” column runs weekly during warmer months of the year. Call the extension office at 630-584-6166 for more information. Feedback on this column can be sent to firstname.lastname@example.org.