Question
We live in Houston and have a crepe myrtle in our backyard that has recently developed yellow and brown spots on the leaves.  I have wiped the leaves to see if there is a powdery residue and there isn't.  I don't see any pests on the leaves either.  This tree is not in the shade.  It is about 3 years old, is a good size, and has been healthy until just a couple of months ago.  Even the new growth at the base is developing brown spots on the new leaves.  Any ideas on what this could be?

Thank you.

Answer
Cercospora Leaf Spot: Leaf spots may appear on crape myrtle that are caused by the fungus Cercospora species during periods of warm, moist weather. Yellow spots (1/8 to ?inch diameter) appear on the upper leaf surface with white-grey sporulation of the fungus on the lower leaf surface. The disease can result in almost complete defoliation of the plant in late summer and fall in susceptible cultivars.

Prevention and Treatment: Provide good air circulation and avoid overcrowding plants. If disease is severe enough to warrant using chemicals for control, thiophanate-methyl (Ferti-loame Halt Systemic Fungicide or Green Light Systemic Fungicide)will control Cercospora leaf spot. Apply all chemicals according to directions indicated on the label