Boxwood borers are many gardeners' nightmares. If they are discovered too late, the plants can usually no longer be saved because they literally suck the life out of them. These annoying caterpillars are very good at camouflage and even their tiny eggs are difficult to detect. Find out in this article how you can recognize and combat boxwood borers in order to properly care for and protect the hedge in your garden.
The boxwood moths are actually native to Japan and China. They were first spotted on the southern Upper Rhine in 2007, and since then the small butterfly has spread and now also lives in the surrounding countries. As beautiful as the butterflies are to look at with their silky white wings and brown edges, the caterpillars cause just as much damage to the popular box trees.
How do you recognize the boxwood moth?
The first sign of an infected boxwood are the small, oval holes in the plant's leaves. These are caused by the caterpillars that feed on the leaves. The dark green caterpillars with dark stripes on the sides of the body are most active between March and October and can destroy the plant within a week.
The voracious caterpillars eat the plant's leaves, leaving faded or brown spots on the shrub. However, the worst damage begins inside the plant and spreads outward.
Other signs of an infestation include the white web-like nests during the pupation phase and the dark droppings on the leaves and twigs.
Use the natural enemies
According to the Nature Conservation Association of Germany eV, the caterpillars of the box tree borer initially had no natural enemies. The reason for this is said to be the plant's poisonous toxins, which they absorb when they eat them.
However, it has now been observed thatcertain bird specieshow house sparrows, great tits and chaffinches attack the caterpillars. Therefore, you can attract natural predators to your garden by placing bird baths and hanging feeders in the garden.
Collect the caterpillars by hand
If your boxwood is already infested with borers, you must fight them immediately as they spread and multiply relatively quickly. You can simply collect them by hand at first. Although this method is time-consuming and requires a lot of patience, it is still very effective. Make sure that the caterpillars are quite fast and hide inside the plant. You can also use a leaf blower or a pressure washer after placing a plastic sheet under the boxwood to catch and dispose of the fallen caterpillars.
Don't worry when collecting the boxwood moths. The caterpillars are not poisonous, but it is better to wash your hands thoroughly afterwards,if the pestshave come into contact with the skin.
Identify boxwood borers and fight them with pheromone traps
The boxwood moth caterpillars are often difficult to detect because they hide well. Therefore, the pheromone traps are a useful indicator of the appearance of the borers, so that you can take immediate action.
These traps contain a synthetic pheromone that attracts the male caterpillars. They serve as an early warning system that shows you when the males are active so you can start treating the plants in a timely manner.
To increase the effectiveness of this method, you can fill the trap halfway with water and a squirt of dishwashing liquid to ensure that the male borers can no longer fly.
Spray the hedge with neem oil
If there is a severe infestation, you can use neem oil to control boxwood borers as the neem seeds contain a natural insecticidal agent known as azadirachtin. It is harmless to beneficial insects such as bees, but kills boxwood moth caterpillars.
Mix 10 ml of neem oil with emulsifier with one liter of water and spray the plants regularly in stable weather. The neem oil works for about 5 days if it is not washed off by the rain. Also avoid using the natural remedy in strong sunshine, otherwise the boxwood leaves could burn.
Spray the affected plants in spring when the pests are still active inside the boxwood and repeat the process in July to increase the effectiveness of the method.
Prevent boxwood borers with algae lime
To yoursBoxwood hedge before pest infestationTo protect them, dust them with algae lime as a preventive measure. This agent strengthens the plant, makes it more resistant to attackers such as caterpillars and supports its regeneration.
Sprinkle the boxwood generously with algae lime powder so that all leaves and parts of the plant are covered and inedible for pests. Leave the powder on for 24 hours and water the plant thoroughly to wash it off. Otherwise, the algal lime can change the pH value of the soil and prevent the plant from photosynthesizing. Do not use more than 3 times a year, starting in spring.
Do you have webs on the trees? Then it is probably the caterpillars of the web moths.You can do that.
