Arborists are seeing less Anthracnose.
The picture above by Famartin (via CreativeCommons) is a sycamore tree with severe anthracnose. Anthracnose is a group of diseases that cause leaf death and a commonly found on Modesto ash and sycamores. As trees leaf out in March and April, anthracnose can spread if conditions are moist. Click here to read more and to learn other tips on how to care for your tree under drought conditions.