Issue 10: Hot in May

aphids on tulip popular

Aphids are feeding and reproducing on many plants at this time of the year.  The picture is of aphids feeding on tulip popular.  Honeydew falling onto furniture, structures, vehicles, other plants and walkways can be a nuisance issue.  These usually require no control efforts.

dunces in May

Some bagworm eggs have hatched and larvae have ballooned to nearby hosts.  Look closely for the ‘dunce cap’ stage of these caterpillars feeding on trees and shrubs.  Applications of Bt now through late June will provide excellent control of these small caterpillars.


pine spittle bug

Pine spittle bug requires no control efforts.  They are just unsightly.

rose slug sawfly damage


Roseslug sawflies are feeding on roses at this time.  Early instars cause ‘window paning’ damage to leaves.  Eventually the remaining dermal tissue of the leaf dries out and falls off the leaf leaving behind a smooth-edged hole in the leaf.

sweek mock orange

Sweet Mockorgange is in bloom to full bloom in Sussex county.  As the sign indicates (from the education gardens) the arborvitae leafminer adult is flying and tussock moth caterpillars are feeding.

All pictures provided by Tracy Wooten, University of Delaware

What’s Hot HL Issue 9?





Currant sawfly (aka imported currantworm) adult.





Currant sawfly eggs on leaf.





Feeding damage caused by currant sawfly larvae






Close-up of currant sawfly larvae

All images of imported currantworm (currant sawfly) were provided by:  Whitney Cranshaw, Colorado State University,  Images for ambrosia beetle, hemlock woolly adelgid & a variety of lace bugs have been posted previously to this site.  Please use the search function to locate these photos.

What’s Hot HL Issue 7?

Pictures of Cedar quince rust have been posted to the website previously.  Please use the search function to locate these images.






Feeding damage caused by bristly roseslug sawfly larvae on the underside of the leaf.  This sort of damage is often called ‘window-paning’.






Roseslug sawfly larva feeding on the underside of the rose leaf.








Close-up of the roseslug sawfly larva.  Roseslug sawfly photos provided by: Brian A. Kunkel, University of Delaware, Ornamentals IPM Extension Specialist