Whitefly Infestation in Pacchysandra

Asked September 10, 2015, 10:26 AM EDT

While I was away for three weeks, whiteflies infested two pacchysandra beds in my yard. I understand that few, if any, pesticides will get rid of a bad infestation because much of the damage is done by larvae. I've resigned myself to cutting back all the plants. Here are my questions: Do I need to dig up the roots and then replant in the spring? Should I treat the soil to get rid of eggs or larvae that remain after I get rid of the plants? Will the winter freeze (if we have one) kill the eggs and larvae? Any other advice about dealing with this infestation would be very helpful. I have attached three pictures of a plant that may have been damaged (not sure this is whitefly damage), a dead area of pacchysandra that is teaming with larvae, and larvae on a leaf.

Montgomery County Maryland

2 Responses

Based on your photos this looks like euonymus scale on your pachysandra. This is a sucking insect that causes yellowing, stunting, and dieback. See our website for more information. http://extension.umd.edu/hgic/armored-scales-groundcovers
At this point we recommend removing all old, dead plant material and thin to improve air circulation and light penetration. Water during dry periods to promote growth. You can spray with horticultural oil once the weather cools. Do not spray in hot temperatures as this can damage the foliage. You do not have to treat the soil.
See our publication for more information http://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG48%20Euonymous%20S...

That's very helpful. I originally thought it was scale but my helpful local nursery assured me it was whitefly. I've now pulled out the infected plants and will spray the beds with horticultural oil as soon as the weather cools a bit. Thanks!