Invasive Red-Necked Longhorn Beetles Found in Odawara Plum Orchards

Officials in Odawara, Kanagawa Prefecture, confirmed the first discovery of invasive red-necked longhorn beetles at a local plum orchard on July 10 [1, 2, 3].

The discovery threatens a critical agricultural hub, as Odawara is the largest producer of plums within Kanagawa Prefecture ^[1]. Because these beetles target trees in the rose family, including plums and cherry blossoms, their presence could lead to widespread destruction of local orchards.

City officials said the findings on July 17 ^[3]. According to reports, more than 10 adult beetles were identified at the site ^[1]. Investigators also found evidence of larval infestation in several trees ^[1].

The red-necked longhorn beetle is classified as a specified invasive alien species in Japan. The pests lay eggs in the bark of host trees, allowing larvae to burrow inside and consume the wood from the interior. This process often kills the tree by destroying its vascular system.

This infestation is part of a growing trend across the archipelago. The beetle was first identified in Aichi Prefecture in 2012 and has since spread to 19 prefectures ^[1]. Local authorities are now evaluating measures to prevent the insects from spreading further into the region's agricultural zones.

Agricultural experts said the beetle's ability to hide within the heartwood makes early detection difficult. By the time adult beetles emerge from the trunk, the internal structure of the tree is often already compromised. The discovery in Odawara marks a significant escalation in the pest's reach into high-value fruit production areas.