Outdoor Plants, GARDEN CARE, PLANT MAINTENANCE
June 9, 2023
Sheridan Nurseries is the industry leader in boxwood cultivation with over 70 acres devoted to growing this exceptional broadleaf evergreen on our farm in Halton Hills, Ontario. Boxwoods are very hardy shrubs that thrive well in our climate but can be susceptible to common Boxwood shrub pests.
It is good practice to regularly inspect your boxwood plants from May to September to ensure they are not showing signs of unwanted visitors.
FOUR COMMON BOXWOOD PESTS INCLUDE
The caterpillar of the box tree moth feeds on boxwood foliage and bark. You can recognize them by their greenish-yellow bodies, striking thick black, thin white stripes and shiny black head. Symptoms of box tree moths include chewed leaves, webbing on the plant, and dark green debris similar to sawdust called frass.
Prune back the affected area and dispose of the clippings in a black garbage bag and place in direct sunlight for up to 48 hours to kill the larvae so they cannot spread to other plants. The affected plants can also be treated with BTK insecticide.
This small, orange fly is one of the most damaging boxwood pests and will cause blistering and small red spots to appear on the leaves. Between late spring and early summer, the females lay their eggs on the underside of the leaves. Upon hatching, the larvae burrow into the leaves and feed on the plant for the duration of the summer. If left untreated, they will overwinter inside the leaves and repeat the cycle in the spring. You can reduce their presence by pruning upon the first site of damage to the leaves and by applying an insecticide to ward off future infestations that season.
Boxwood psyllids lay their eggs in the boxwood plants in the fall, overwinter on the plant, and then hatch in the spring. Upon hatching, they immediately begin feeding on the plant, causing the leaves to cup and curl.
Their damage is primarily cosmetic, and pruning out the curled leaves as soon as deformation appears will keep psyllid from spreading. Prune out and destroy all affected branch tips and spray the plant with horticultural oil or insecticidal soap.
Deposit the pruned clippings into soapy water or a 15% vinegar or bleach solution to kill the nymphs to prevent them from reinfecting the plants.
A Boxwood mite is a spider mite that feeds on the underside of the leaves, causing tiny white or yellow spots on the plant. Boxwood mites are most active in the spring and early summer and, if not treated, can cause defoliation. Treatment includes washing the plant with a steady stream of water or using a horticultural oil, insecticidal soap, or miticide/insecticide.
Two suggestions for pesticides include
Safer’s® BTK Insecticidal Concentrate
Apply this safe and effective insecticidal concentrate to protect your Boxwood. We use this product in our nursery and garden centres as a preventative measure and recommend it for use at home.
End-All Miticide-Insecticide-Acaricide 1L RTU
Controls all stages of aphids, whitefly, scale, spider mites, mealybugs, caterpillars, beetles chinch bugs and other listed insects.
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