Black Spots on Chard Stems - Ask Extension
Please see attached photo of a spots that recently appeared on our very healthy and plentiful crop of chard. The chard was growing with nasturtiums th...
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Black Spots on Chard Stems #877563
Asked July 16, 2024, 10:59 PM EDT
Please see attached photo of a spots that recently appeared on our very healthy and plentiful crop of chard. The chard was growing with nasturtiums that recently died back. Can you tell us what has infested our chard and what we can do? Not all of the chard has the spots but about 1/3 or more does.
Baltimore County Maryland
Expert Response
This looks like damage from a pest called the tarnished plant bug (TPB) It has piercing sucking mouthparts and "stings" the ribs and this damage is the result. It is a hard pest to deal with since it has a wide host range (alfalfa, fruit crops, veg crops, etc) and is around all summer. The good news is that it is more unsightly than damaging so you can still use the foliage.
In the future you can use row covers or insect mesh netting to help protect seedlings and transplants from TPB feeding as they over winters as adults.
Emily
Thank you. We had mesh netting over them and I removed it. Will keep it on next year. Appreciate your help.
Cynthia
