The following are some pests currently active in DE landscapes that you should watch for.
First generation fall webworm is being found on apple, crabapple and persimmon. Don't think it's the old tent caterpillar tents! Mechanical disruption of the web now will lessen the second generation.
The “Shothole” damage from Tortoise beetle feeding is prevalent on annuals (Ipomea ,etc.) and some perennials.
Rose midge is active this year again in many locations. Look for the “blighted” shoot tips on the terminal growth only.
Powdery mildew is all over crepe myrtle, lilacs, and other shrubs and flowering trees due to warm moist conditions combined with succulent new growth. Fungicides and sanitation may be required to prevent spread or overwintering.
Cicada Killer wasps are solitary wasps and are very unlikely to sting. Males fly at people, dogs, cats, other insects, etc. but are unable to sting. Females prefer to dig holes and sting cicadas. Treatments are rarely warranted.
Information from the current edition of the Ornamentals Hotline Newsletter from the University of Delaware Cooperative Extension.