Spots on mint leaf plants in backyard

Asked June 29, 2019, 3:27 PM EDT

My mint leaves have something on them that leaves rust-like dark spots. I have tried cutting off the spotty leaves. I have seen a small stripped bug on leaf twice but it flies away so I don't know if it is doing damage or eating something left by the "causer" of the spots. Should I continue this or just cut them down to the ground? Mint leaves seem quite hardy. Thanks!

Hennepin County Minnesota

1 Response

4 lined plant bugs can cause dark spots on leaves. See the links below to see if the leaf damage is what you have been seeing. If it is not, feel free to respond and attach a photo for our us to review. https://extension.umn.edu/yard-and-garden-insects/four-lined-plant-bugs http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/insects/plant-bugs/tarnished-and-four-lined-plant-bugs.aspx 4 lined plant bugs don't fly, however, so may be different than the insect you saw. Plants can survive some of the damage from 4 lined plant bugs. But large amounts of damage can be detrimental to some plants. Interestingly, the following link notes the use of mint to keep the bugs off of other plants. https://www.vegedge.umn.edu/pest-profiles/pests/four-lined-plant-bug