I have observed white specks on the leaves of my boxwood plants. Any help with this matter would be appreciated.
If the white specks are observed on the under side only of the leaves, the specks could be whiteflies. Insecticidal soap solutions (made up according to product label instructions) sprayed on both sides of the leaves may be helpful. This method eradicates the adult insect only, so repeated applications will be necessary to catch all the adults maturing through eggs, nymph, pupa and adult stages. Another method is to buy sticky yellow pad traps in garden stores. Place the traps close to the leaves and the whiteflies, attracted to the colour yellow, will land on the traps and get stuck on the glue. Thirdly, earthworm castings, when added to the soil of whitefly-infested plants has been found to repel the flies within a few weeks. Earthworm castings can also be purchased in garden stores.
If the white specks are also on the top of the leaves, then it could be the Boxwood Spider Mite, Eurytetranychus buxi. These mites show up as small silver-coloured dots on the leaves, usually old leaves, and white webbing. It is actually tiny spherical eggs or pieces of broken eggshells that appear as specks or spots. To find the mites, hold a sheet of white paper under a branch and tap the branch sharply. Some mites will drop onto the paper, where they appear as tiny specks about the size of a pencil dot as they crawl about. Mites thrive when it is warm and dry so they can be removed in similar ways to the whiteflies, by being sprayed off with a hose or sprayed with insecticidal soap. Weeds should be controlled around plants so mites don’t have extra hiding places and finally, plant-based miticides can be used. Two examples of miticides are pyrethrum (made from a plant closely related to the chrysanthemum) and neem oil, derived from the neem tree. These two miticides can likely be found at larger garden stores.
This link will provide more information on boxwood diseases and insect pests:
https://www.clemson.edu/extension/hgic/pests/plant_pests/shrubs/hgic2052.html