If any of you have Ligustrum (aka Privet), plants in your landscape, there’s a good chance they may have Cercospora Leaf Spot on their foliage.
Symptoms to look for include irregular brown spots with yellow margins on the upper leaf surface and brown spots with purple margins on the underside. These symptoms are particularly noticeable on older plantings which also display thinning canopies, and although more noticeable in late summer-fall, can occur anytime day temperatures are 7o-80 degrees and down to 60 at night. This fungal disease at best is difficult to control, and although many homeowners have this problem, they consider it of minor importance and ignore any treatment. Only after several years of decline do they become concerned, and by that time there’s not a lot that can be done, so they remove the infected plants.
By now you may be asking is there anything I can do, and my answer is yes. Avoid over watering, especially at night, clean up any infected leaves, thin out the canopy to provide good air movement, and provide good culture. Applying repeated applications of Daconil, Dithane, or Cleary 3336 also seem to help. Remember, when using any pesticide, always read and follow label directions.
For more information about this disease click here.