Identifying and Treating Scale or Mealybug Infestations on Boxwoods

Identifying and Treating Scale or Mealybug Infestations on Boxwoods

Boxwoods are prized for their dense, evergreen foliage and versatility in the landscape. However, they can fall prey to tiny pests that appear as white, fuzzy spots on the bark. If you notice these spots moving or see fine cilia under magnification, you are likely dealing with scale insects or mealybugs—both sap-feeding pests that can weaken and eventually kill the plant if left untreated.

Signs of Infestation

• Tiny white, cottony or waxy spots on branches and bark
• Spots that appear to move or have fine hairs (cilia) when examined closely
• Gradual yellowing or thinning of foliage
• Branch dieback in severe cases

Effective Treatment

A systemic insecticide such as Bayer Advanced Tree and Shrub Insecticide (containing imidacloprid) provides reliable control. Mix the product with water according to label directions and pour it around the base of the plant. The active ingredient is taken up through the roots and translocated throughout the plant, killing feeding insects within a week. A single application also provides protection against reinfestation for up to a year.

Application Tips

• Apply when soil is moist but not saturated.
• Measure the height and width of each plant to determine the correct dosage.
• Avoid overhead watering for 24 hours after application to allow uptake.

With prompt treatment, your mature boxwoods can recover and continue to thrive for years to come.