Milkweed Bug is Killing the Plants
Common milkweed (Asclepias syriaca) is hardy to U.S. Department of Agriculture zones 3 through 9, and unfortunately, it attracts a few different types of milkweed-specific bugs that can harm the plant. Not many insects are able to feed on these plants due to the toxin-filled leaves, but there are some bugs that have evolved to be able to ingest these chemicals without getting poisoned.
Pesky milkweed bugs come in two different species: the large milkweed bug (Oncopeltus fasciatus) and the small milkweed bug (Lygaeus kalmi). These brightly colored insects are bothersome, but luckily, there are several ways you can stop them in their tracks and prevent them from destroying your plants.
How to Identify Milkweed Bugs
Milkweed is the single most important source of food for the threatened monarch butterfly, so it's especially important to ensure that this plant is healthy and thriving. First, you should be able to identify the milkweed bug in order to then take action against this pest. If you see red mites on milkweed, you're probably looking at a milkweed bug.
Insects that have the ability to eat milkweed have a warning coloration that advertises their toxicity. This is why these kinds of bugs often have vibrant red, black, gold or orange markings, which makes them distasteful to predators. The nymphs look like adults, though they do not have full wings, and their color pattern is slightly different. The bugs' eggs begin as light yellow and change into a deep reddish color.
Usually, you'll notice milkweed bugs crawling all over your plant, especially once the seed pods have burst open. The bugs feed on the seeds by piercing the seed pod, and they can be found (in all stages of growth) on the plants in mid-to-late summer.
How to Prevent Milkweed Bugs
To stave off eggs on milkweed and keep bugs from harming your plants, take the following preventative measures:
- Remove leaf litter and spent stalks in the fall. This will prevent overwintering sites.
- Try planting several species of milkweed in different areas of your garden and home. That way, if bugs take over and destroy one plant, you'll have plenty of others.
- Keep up with healthy pruning practices.
To get rid of milkweed bugs on your plants, try the following:
- To start, you may want to try living with the damage the bugs are doing to your plant, as milkweed bugs rarely actually destroy milkweed.
- To get rid of existing bugs, try first spraying them with a gush of water from the garden hose.
- Brush the bugs aside with a detail brush to get rid of them.
- Use a spray bottle filled with water and a couple tablespoons of mild dish soap to remove the insects. Soapy water usually does the trick quite nicely.
- If there aren't very many bugs on your milkweed plant, you could try to pick them off manually. (You'll still want to try spraying off the bugs with a hose first.)
Tips for Caring for Milkweed Plant
Growing a healthy milkweed plant will attract monarch butterflies and other beneficial pollinators to your garden.
- Milkweed prefers full sunlight.
- To ensure successful germination of seeds, plant milkweed in a smooth, clump-free soil bed worked to a fine consistency.
- Plant milkweed in groups of six or more, spacing plants roughly 10 to 24 inches apart.
- Common milkweed doesn't require much watering except for in the driest conditions.
- Since milkweed is an invasive plant in nature, it does need to be controlled.
- No feeding is necessary for this hardy plant.
- Plant milkweed in the fall for best results. If you want to start in spring, the easiest way is to buy potted plants and transplant them directly into your garden beds.
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