Fungus

Asked February 4, 2020, 2:48 PM EST

Been fighting fungus for a few years. It destroyed my bed of thick pachysandra although I sprayed it with copper fungaside I got at Benkes. Eventually tore it all out and added several layers of new soil. Even so I have trouble getting new pachy to root. Now I believe there is fungus in the English boxwood. White powdery dust on foliage towrd the center of the plant-i.e. not easily exposed to sunlight. The box leaves make tiny cups and roselike heads at the ends. How do I spray inthere? Do you have a test fo the fungus? Is there a DC extension agent? Thnaks Elizabeth Eby 202/546-0825,

District of Columbia County District of Columbia

1 Response

The University of the District of Columbia does have an Extension office. You can contact their office to learn who may be best suited to help you: Renee Bellis (Staff Assistant), 202.525.9721 and renee.bellis@udc.edu.

The problem that you had with your groundcover pachysandra was likely due to a disease pathogen called volutella. While groundcovers are less work than lawn, they do need some management over time to do well, which includes thinning, removal of debris, fallen leaves etc. Leaves staying wet for too long can lead to disease issues. Here is a page about it and what you may have seen:
https://extension.umd.edu/hgic/topics/volutella-dieback-pachysandra-groundcover

Fungicides are not curative, they only prevent new symptoms. We would not encourage the planting of new pachysandra as it has become invasive in our area.

We don't think that what you are seeing on your boxwood is a fungal problem. Your description sounds like it could be related to an insect pest called Boxwood Psyllids. See more about that here: https://extension.umd.edu/hgic/topics/boxwood-psyllid-shrubs
Boxwood are best maintained not by shearing, but by selectively thinning so that light can reach the center of the plant. This helps keep the plant healthy and easier to reach leaf surfaces with chemical treatments. Now is the best time to do that. Here is a page on Boxwood culure and disease:
https://extension.umd.edu/hgic/topics/volutella-dieback-pachysandra-groundcover

And a How to Prune Boxwood video: https://www.youtube.com/watch?v=3i8mcoKapeY&t=138s


Christine