Common milkweed weakening

Asked July 16, 2017, 3:24 PM EDT

Hello, many of my milkweeds are developing wrinkled, yellowing tops. At first I thought the plants came up from seed, but I'm wondering if they might have a disease. If so, should I pull them? Anything else I need to do to protect future plants? Are they useful or harmful to monarchs? I am trying to help with their numbers and don't want to create more problems for them. Thank you

Wright County Minnesota

4 Responses

We can't be sure without laboratory analysis, but we think the plants might have been affected the cucumber mosaic virus. Despite its name, this disease is not restricted to cucumbers. It affects many kinds of plants and is spread by aphids and cucumber beetles.

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Removing the plants may help prevent its spread.

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I have seen a similar appearance when common milkweed is impacted by glyphosate herbicides. Since they spread by rhizomes, it is possible that weed control applications made some distance from the plants in the garden may result in a herbicide being translocated back to the garden plants through the rhizomes. I have this occurring on my property right now.

Thamks, I guess that's possible. I'm tackling buckthorn too. A catch 22 situation.