spots on collard green leaves - Ask Extension
Hi,
My collard greens, growing in a little greenhouse, are developing small white spots on the leaves. Otherwise, they seem very healthy. The spots ...
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spots on collard green leaves #879238
Asked July 29, 2024, 12:56 PM EDT
Hi,
My collard greens, growing in a little greenhouse, are developing small white spots on the leaves. Otherwise, they seem very healthy. The spots show up on older leaves, new growth in the center starts out spot-free. Can you tell me what is causing these spots, if they are harmful, and how I can prevent them? Thank you!
Wayne County Michigan
Expert Response
This looks like damage from thrips (Thysanoptera). Thrips are small insects that are a common pest in greenhouses and other indoor growing spaces in Michigan. There is no one-size-fits-all approach to thrips management in greenhouses. I would recommend starting by using sticky cards (yellow or blue), to measure the population and determine where they are in their life cycle. There are effective biological controls for thrips, but they tend to work best when thrips populations are low. You can read more about thrips biological control in this article from MSU Extension: https://www.canr.msu.edu/news/timing_the_release_of_beneficials_is_critical_to_biocontrol_success