Spearmint - disease or critter?

r.p.thomas

All of our Spearmint has developed whiteish patches, the leaves then go brown and disfigure or drop.  Can anyone identify the problem and suggest a treatment please?

Borderline

I suspect that might be advanced stage of Spider mite damage. Have you seen webs between leaves? Unfortunately difficult to see. They tend to thrive in dry and warm areas. Keeping plants well watered should hold them back. 

r.p.thomas

Thank you.  Yes, there have been webs in that part of the garden.  That's very helpful (and reassuring).

Borderline

I recommend you cut them all down and water well. They should grow back better.

PeggyTX

I concur with Borderline, as I just cut down my spearmint as it was struggling and yellowing off in our 38-39ºC heat.    It's coming back nicely in just 2 weeks!