Emerald ash borer Agrilus planipennis Fairmaire – a threat to deciduous trees

The emerald ash borer Agrilus planipennis Fairmaire is a real threat to deciduous forests. This dangerous insect has already been spotted on the territory of Ukraine, in particular in Luhansk and Kharkiv regions. In this article, we will talk about what the emerald ash borer looks like, consider the most common signs of its activity, and pay attention to the peculiarities of the insect’s life cycle.

What does the ash borer look like?

The colour of the insect is emerald green, with a golden, bronze or purple sheen. The size of the insect can range from 7 to 15 mm.  These beetles live in the crowns of trees and feed on their leaves. If the weather is warm, the borer can fly up to 20 km in search of a tree to feed on. In bad weather and at night, the insects can hide in tree crowns and bark cracks. The larvae live in the bark of the plant and feed on bast during the summer.

The larval passages are curved and can expand as the larva grows, its length can be up to 32 mm. The passages are often clogged with drill flour. Females lay their eggs in cracks in the bark on the trunk and in the lower part of the tree branches.

Emerald ash borer Agrilus planipennis photo from the website Agrarians United

The most common signs of ash borer activity

Ash Borer is a danger to such deciduous tree species as ash, oak, aspen, maple, hornbeam, linden, hazel, walnut, alder. The insect mostly harms healthy plants.  If a plant is damaged by ash borer, it usually dries up within two to three years. The most common signs of ash borer damage are: the presence of larval passages under the bark, such plants have a sparse crown, and branches show swelling, cracks, necrosis, and the crown dries out from top to bottom.

Features of the life cycle of ash ash borer

Under natural conditions, ash borer is particularly common in deciduous and mixed forests in Korea, northeastern and central China, Japan, extreme eastern Mongolia, and Taiwan.

The insects can form flight holes on tree trunks and branches, which are shaped like the letter D. If the ash borer is actively spreading, it can cause serious damage to your plants within a few years, which is why early detection of the signs and effects of the insect is crucial to maintaining the health of green spaces and reducing its negative impact on the ecosystem.

As you can see, the ash borer can harm various species of deciduous trees, so if you notice even the slightest signs of this insect on the plot or somewhere nearby, you should act proactively immediately.

Contact the team of the Green Clinic Ecosystem Phytopathology Centre by phone: :+380632851405