Boxwood under siege: Battling the invasive box tree moth
Boxwood is a popular choice for many gardens—elegant, evergreen, and easy to shape. Unfortunately, its biggest enemy in recent years has been the box tree moth. This seemingly harmless insect can completely destroy even mature, multi-year plants in a short time. How can you recognize and effectively combat it?
Box tree moth (Cydalima perspectalis) is an invasive species originating from Asia. In recent years, it has spread across almost all of Europe. It appeared in Poland relatively recently but quickly began wreaking havoc on boxwoods in gardens.
The main culprits are the moth larvae. They are light green with dark stripes and can grow up to 1.6 inches long. These larvae feed intensively on the leaves and young shoots of boxwood, significantly weakening the plant and, in extreme cases, leading to its death. Infested shrubs quickly lose their leaves, start to dry out, and noticeably decline in appearance.
Signs of box tree moth feeding
The first concerning symptom indicating the presence of the box tree moth is the appearance of fine webs and black lumps of feces on the plant's leaves. Over time, more extensive damage appears: the leaves turn yellow, become shredded, and eventually, entire sections of the bush start to die.
It's crucial to regularly inspect the inside of the plants, as the larvae often begin feeding from the center of the bush. Hidden deep in the thicket of branches, they remain invisible in the early phase of the attack, making it difficult to take swift action.
Dr. Mateusz Sowelo, curator of the collection at the Botanical Garden of Adam Mickiewicz University in Poznań, emphasized in an interview with tvnmeteo.pl that the presence of this insect on boxwood can result in the complete destruction of the plant within a few days.
Effective methods for combating the box tree moth
The most crucial element in the fight against the box tree moth is to act swiftly as soon as the first signs of its presence are noticed. One highly recommended method is using biological preparations containing Bacillus thuringiensis bacteria. These agents are safe for both humans and animals and are very effective in eliminating the insects.
Sprays should be applied at regular intervals, especially in spring and summer, when the moth goes through various developmental stages. In cases of severe infestation, it is also advisable to mechanically remove larvae and prune infested shoots.
Take care of plants before a problem arises
The box tree moth thrives in dense, moist, and poorly ventilated shrubs, so prevention is key. It's worth pruning boxwood to maintain good airflow, reducing its attractiveness to female moths looking for egg-laying sites.
Regularly removing dry leaves and organic debris from under the plants can also decrease the risk of pest development. Applying pheromone traps is another effective strategy. These traps help monitor the presence of adult moths, enabling proactive measures before larvae appear.
