The boys and girls at the lab must have had a good laugh.Back came the lab report saying;"Your plants have Edema and they will recover".Anyway,this is caused by periods of cloudy,cool weather when the plants fill their tissues with water.Then,out comes the sun and the plants can't get rid of the water fast enough so the cells rupture.It's unsightly but not fatal.New leaves grow and the damaged ones drop off.Damaged leaves do not recover.
Pic is the underside of the leaf
