I dunno... you have different bugs than I do... but I'd suspect any leaf eating bug... slugs... whatever... I wouldn't really plant them in sandy soil, they don't need drainage, but it doesn't have much to do with this problem.

dunno what the pest is, but I suspect the origin of the problem is cultural. Mint is a plant that likes fairly poor soil. It doesn't need to be super draining and super draining is probably less than ideal. It also doesn't need fertilizer and if it is getting fed then it can stress it out. For me it also does best in full sun, but you have more intense sun than I do. If the plant isn't doing well it is more susceptible to bugs. I don't think I have ever seen mint get bug damage in my yard, but as Heathen noted, we don't all have the same bugs.

Try to find some plain old dirt to plant it in and leave it alone. By plain old dirt I mean a clay/loam soil, not sand. For pots you might try the loam based potting mixes if you can find them rather than the peat based, but peat based is fine too. I have some mint that is growing in straight compost (4" on top of clay soil) and it seems happy there without food or water (other than the rain).

I know mint grows fine in the ground in central FL and the 'soil' is all sand with way too good drainage. I wouldn't put potting soil in the ground, I think doing that right around a plant tends to cause more problems than it solves, I would instead amend a larger area of soil by mixing in compost. You do have to water mint it likes water. You might give it a few days to see if it perks up, if not maybe move it to an area that gets more water like near a gutter outlet or under an eve (not standing water but more water-you kinda have to work to drown mint though it's possible, my mom's done it). You might mulch too to help retain water.

My mint is all munched on too. I've seen cabbage loopers (I believe-light green caterpillars that make a loop when they move) on them and the basil next to it, you could take care of this with Bt (Dipel).

I mostly blame crickets at night for the mint, but they were also eating the leaf heads right off my garden seedlings. That made me mad. So, I went on a murderous cricket rampage, placing glasses filled with a mix of molasses, lemon, vanilla and water all about my garden. The crickets happily dove right into the glasses and drowned. This seems to have helps my seedlings, I'm not sure about the mint yet.

Oh, holes in just the center of plant's leaves often suggests snails and slugs, look at night with a flashlight for them.

I had problems with my mint dying off no matter what I did for years. Something kept eating holes in the leaves or part out of the center and it never looked healthy. I didn't figure it out until I saw the culprit in action....

my cat. LAYING on the plant and grazing, happy as a clam.

The vet tells me that almost all mint has a lesser degree of the active ingredient in catnip, so can prove a temptation to some cats.

I have just started an experiment.....to get the whiteflies that LOVE my mint. I put yellow cards on sticks in the flower boxes, and slimed petroleum jelly all over them for stickiness (I really can't afford tanglefoot nor am I at all sure it's available here in Israel). We'll see if the whiteflies get trapped in the goo instead of happily taking over my mint.....but still I see little tiny patches where some kind of leaf miner is making inroads......batya

As an update, I used Safer Caterpillar Killer which contains Bt=Dipel=Bacillus Thermogenesis-or something like that. On my mint, the cabbage loopers (or some sort of tiny green caterpillar that looked like it) were taking over. I don't mind sharing but they wern't good sharers. Anyway, good spray one evening (have to spray in evening because Bt degrades in sun) took care of em. My mint is making a comeback. The cabbage loopers eat on the bottom of the leaves so look under the leaf, they were also taking over one of my sages.

As for leaf miners, I don't have anything that really works except I constantly pick off the infested leaves off my basil or on my vegies (where I dont want to kill a whole leaf), I pinch the beginning and end of the tunnel between my nails to kill the little guy inside the leaf. Its a never ending fight for that one. Try and pick off early to get it under control quick.

I have a similar problem with something eating my mint. I found a small beetle embedded in the mint. It is brownish/gray with dark markings on it. I have been unable to locate the species, since there are thousands of different types of beetles. I am assuming that this is the culprit. If anyone has any knowledge of this beetle and it's relation to mint, I am wide open to any help/answers on eliminating this pest! Thanks! ~Monica

Try taking a photo of the bug, descriptions are hard to diagnose.

Hello, I know this is an old thread but I've been having problem with my mint. There are some bugs feeding on it . they look like little grass hoppers. Any idea on how to get rid of it?

@Jhoan try neem oil or an insecticidal soap. just don't cook the plants by spraying it on when the sun is high. Best early morning