Mulberry bark beetle

The Mulberry bark beetle (Cryphalus morivorus) is a wood-boring insect belonging to the family Curculionidae, subfamily Scolytinae (bark beetles). This beetle specifically targets mulberry trees (Morus species), representing a significant threat to sericulture and ornamental plantations where mulberry trees are widely cultivated.

The beetle primarily attacks the stems and branches of host trees. While it frequently targets weakened, stressed, or diseased mulberry trees, high population densities allow it to successfully colonize healthy trees as well. The resulting damage to the phloem and cambium layers severely hampers the tree's physiological processes, leading to reduced vitality.

The life cycle is largely hidden beneath the bark. After boring into the tree, the female constructs galleries where eggs are laid. Upon hatching, the larvae excavate their own feeding galleries perpendicular to the main tunnel, consuming the nutrient-rich inner bark. The beetle usually completes its life cycle within a single season, though climatic conditions may lead to multiple overlapping generations.

The infestation is characterized by specific external symptoms that indicate internal damage. Owners should look for small, circular entry holes in the bark, often accompanied by frass (a sawdust-like waste product) visible in bark crevices. As the gallery system expands, the tree's vascular system is interrupted, resulting in crown dieback, chlorosis, and eventually tree death if not managed.

Effective management requires a combination of silvicultural practices and chemical interventions. Key measures include strict orchard hygiene, specifically the prompt removal and destruction of infested wood to eliminate breeding sites. During the peak flight period, systemic or contact insecticides may be applied to the trunks to kill adult beetles before they enter the bark. Maintaining optimal tree health through proper fertilization and irrigation also reduces susceptibility.