Buxus sempervirens, known by the common name Buxbaum, is one of the popular ornamental trees for hedges and topiary trees. But during the growth phase it happens that the parts of the plant are attacked by pests.
Which pests attack Buxbaum and how can you combat them?
Bux tree pests such as box tree borer, box tree psyllid and box tree spider mite lead to leaf damage, spoon leaf disease and discoloration. Fight them with high-pressure cleaners, neem oil, roundworms, Bacillus thuringiensis or rapeseed oil preparations and choose resistant varieties.
Boxwood moth
The butterflies lay their eggs inside the box trees. Their caterpillars are green in color and have a black pattern. They develop webs and eat the leaves from mid-March, working their way from the inside out and leaving the leaf veins standing. They feed on the green bark on the shoots and gnaw their way through to the wood. The branches dry out and die.
You can do this
A timely approach increases the chances of success of manual control methods. Blow out the wood with a high-pressure cleaner to minimize boxwood borer infestation. Wrap the crown in dark foil so that the pests die in the heat. Bushes that are heavily infested must be pruned back vigorously. A treatment with roundworms (€7.00 on Amazon) helps here, which you put in water and distribute with a sprayer. Biological preparations containing the bacterium Bacillus thuringiensis prove to be helpful in the early stages.
Boxwood leaf flea
Fleas on boxwood appear between May and June, laying their yellowish eggs under the outer bud scales until July. The egg clutches overwinter so that the larvae hatch next spring. They ensure that young leaves curl upwards and form a cup. This spoon-leaved appearance is evident in densely packed and young leaves on shoots that are in the process of growing. The sucking activity creates galls where you can observe wax secretions.
What helps against it
If you detect an infestation early, cut off the affected shoot tips generously. If large populations have formed, it makes sense to combat them with preparations containing neem oil. Opt for less susceptible varieties such as 'Elegantissima' or 'Blauer Heinz'
Boxwood spider mite
Since spider mites prefer dry and warm weather, they are rarely a problem outdoors. During hot summer months, pests can still spread. The leaves have stripe-like light spots, with young foliage particularly affected. If the infestation is severe, the leaf surfaces appear mottled. It rarely happens that entire branches are surrounded by webs. Encourage natural enemies such as predatory mites. A spray with preparations containing rapeseed oil clogs the animals' breathing openings, causing them to suffocate.
Make and use rapeseed oil preparation:
- mix one liter of water with 250 milliliters of rapeseed oil
- spray affected trees twice a week
- Don't leave out the undersides of the leaves and the inner shoots
Tip
Under favorable conditions, up to six generations develop in a year. Ensure a moist microclimate, as wet conditions drastically reduce stocks.