Boxwood blight - Ask Extension
Do my boxwood have psyllid or leafminer?
Knowledgebase
Boxwood blight #836036
Asked June 16, 2023, 5:49 PM EDT
Do my boxwood have psyllid or leafminer?
Oakland County Michigan
Expert Response
I don't see in your pictures significant symptoms of boxwood psyllid. Psyllid causes cupping of leaves, which I don't see in your photographs. Psyllid also may affect twig growth, but the damage caused is purely aesthetic and not as destructive as other boxwood pests. The boxwood psyllid is a common pest of all boxwoods, but the American boxwood (Buxus sempervirens) is most susceptible. The link below will give you additional information about pests that attack boxwood:
https://www.canr.msu.edu/news/boxwood_insect_pests
I' not sure what the gray material in the leaf of your first picture is, but if it's only apparent on a few leaves, it's not likely anything to worry about. The yellow leaves could be caused by a lack of moisture. We had the 2nd driest May on record. Without additional moisture in that kind of drought, leaves can yellow.
I suggest you give some extra care to your boxwood and keep it well watered, especially under dry conditions. If your issue continue to occur, please let us know.
https://www.canr.msu.edu/news/boxwood_insect_pests
I' not sure what the gray material in the leaf of your first picture is, but if it's only apparent on a few leaves, it's not likely anything to worry about. The yellow leaves could be caused by a lack of moisture. We had the 2nd driest May on record. Without additional moisture in that kind of drought, leaves can yellow.
I suggest you give some extra care to your boxwood and keep it well watered, especially under dry conditions. If your issue continue to occur, please let us know.
Thanks for your prompt response. There are cupped new leaves generally at the ends of branches with tiny white eggs(?)inside and something that looks like larvae on the outside of some leaves. Also tiny gnat size flies when branches are disturbed. I bought some Bonide Eight Insect Control (lambda-cyhalothrin) but is there something better you could recommend?
Boxwood Psyllid (Pyslla buxi)
Boxwood psyllids are small (1/16-inch), grayish green insects that
are normally covered with a white, waxy, filamentous secretion that
partially covers the body, providing protection from parasitoids and
sprays of pest-control materials. Eggs overwinter and hatch into
yellowish nymphs that begin feeding as soon as buds begin to open in
early spring. The first-instar nymphs feed by sucking plant fluids from
terminal leaves as they unfold and expand in spring. Their feeding
causes leaves to yellow, curl, and form a cup (Photo 5), which conceals
and protects the nymphs. There is one generation per year.
The links below will give you some control options. Chemical control generally is not warranted, but if you choose to use a chemical pesticide, be sure to choose one that states that it controls boxwood psyllid on the label. Read and carefully follow all instructions on the label.
https://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/insects/psyllids/boxwood-psyllid
https://ipm.ucanr.edu/PMG/PESTNOTES/pn7423.html
