Milkweed bugs are a foe in the garden and here is why.
1. They consume milkweed plants, butterfly eggs, and small caterpillars.
2. They have no real predators (a common trait of milkweed consuming insects due to the toxicity of the milkweed making the insect taste bad).
Species: O. fasciatus
Now that we have labeled Milkweed bugs (Oncopeltus fasciatus for you science nerds) as a foe, we should also note their impact on your landscape is typically minor. Milkweed bugs do not have natural predators due to their color and toxicity. Much like monarch caterpillars, milkweed bugs use the toxins found in milkweed plants in order to make them less favorable to predators such as birds. The good news is that their damage to milkweed plants is usually not significant enough to completely destroy the plants or cause any concern for gardeners.
Small milkweed bugs can appear similar to aphids while they remain in their juvenile stage. These wingless milkweed bugs still have the same appetite as the adult forms. BUT, they typically are found feasting on milkweed seed pods in order to get the necessary nutrients they need for development. It is believed that partial prevention and control of milkweed bugs can be achieved through pruning of seed pods. Removing pods removes the food source for young milkweed bugs therefore restricting their growth and development to adult bugs that can reproduce.
If you find that their impact in the garden is more than you'd like, the recommended treatment is to remove these bugs by hand into a cup of soapy water. Spraying these small bugs with a hose can also help remove them from your milkweed temporarily. Adult winged forms will return quickly but nymphs will take longer to return.
Chemicals should be avoided as they will also harm the butterflies and their larvae. We also want to encourage all gardeners to allow their gardens to be as close to a true ecosystem as possible.
What is your experience with milkweed bugs? Keep the conversation going by commenting below.