[2] In Europe, species such as A. Sulcicollis Lacordaire, A. angustulus Illiger, and A. biguttatus have been identified as significant contributors to oak decline due to their development pattern.

Laboratory studies have shown that they also use volatile cues, known as pheromones, to inform their choices and locate feeding and mating sites.

Agrilus biguttatus show a preference for laying their eggs and allowing initial larval development to occur on the warmer, south-facing side of host trees.

A study measured the development rates of A. biguttatus in terms of the time it takes for the eggs, larvae, and pupae to reach adulthood.

The study found evidence to support that the beetle's distribution is limited by its thermal requirements, and it may not be able to survive or reproduce effectively in cooler regions.

[7] Their life cycle is prominently influenced by local conditions, with temperature and health of the host tree being crucial factors.

In laboratory settings, all larval samples must undergo a period of cold temperatures, to mimic overwintering, to progress in their development.

Following pupation, the adult beetle emerges through a D-shaped exit hole, typically measuring 2.5 to 4 mm in diameter.

One of the major symptoms of AOD is the presence of black fluid seeping from cracks in the bark, which often leads to the tree's death within a few years.

However, A. biguttatus, considered a secondary pest to oak, poses a serious threat by invading weakened trees before they can undergo the process of recovery.

The decline of oak trees in Europe is believed to have been exacerbated by warmer climates and drought, as those conditions are optimal for A. biguttatus growth and host invasion.

Documented evidence shows Agrilus pest incidence in Germany, France, Hungary, Poland, and England, contributing significantly to the increase in tree mortalities.

Agrilus biguttatus often exploits weakened trees, and dark fluid is produced when bacteria enter the wounded oak bark.

Presence of A. biguttatus has also been found to invite pathogenic honey fungi, Armillaria, to grow in the stems of oak trees.

[6] Despite fluid leakage being a symptom of oak decline, mid-instar larvae have been observed to drown in their galleries from these excretions, thus minimizing their spread through the tree's vascular tissue.

Furthermore, this defense is particularly effective against early larval instars, which have slower feeding and movement rates, enabling the host's calluses to suffocate them within the galleries.

Common strategies for controlling this beetle in Britain include the following: Removing heavily infested stems, particularly those exhibiting sudden and rapid decline, significant foliage and twig loss, and signs of Agrilus presence like exit holes and galleries beneath the bark can help reduce the beetle population.

[7] Notably, to avoid creating sunny open areas that attract female beetles seeking oviposition sites, planting trees that can provide shade, particularly along the southern side of woodlands, can be beneficial.

[7] When insecticides are applied to the tree's surface before adult emergence, there is evidence supporting its efficacy in controlling beetles in their pupal chambers within the outer bark.

Common predators of A. biguttatus include: the European red-bellied clerid (Thanasimus formicarius), and the wasp Dolichomitus imperator from the family Ichneumonidae.