Hemp tumbling flower beetle

Mordellistena cannabisi is a species of beetle belonging to the family Mordellidae (tumbling flower beetles) within the order Coleoptera. It is recognized as a specialized pest of hemp (Cannabis sativa), where its larvae cause significant internal damage to the plant stems.

The host range is primarily limited to industrial hemp plants. The pest is particularly damaging because the larvae bore into the central pith of the stems, creating long tunnels that disrupt the vascular system of the plant, which is essential for nutrient transport and structural stability.

The life cycle begins with adults laying eggs on the hemp stems. Upon hatching, the larvae immediately bore into the tissue. The entire larval developmental stage occurs inside the stem, protecting them from predators and environmental stressors. Adults emerge through small exit holes, typically in late summer, and mate to begin the next cycle.

Damage assessment shows that infested plants exhibit stunted growth and reduced fiber quality. In severe cases, the structural integrity of the stem is so compromised that plants collapse under strong winds or heavy rain. Furthermore, these feeding galleries can facilitate the entry of various pathogenic fungi, leading to stem rot.

Integrated pest management (IPM) is essential for controlling this beetle. Key strategies include:

• Strict sanitation by removing and destroying crop residues after harvest.
• Deep plowing to bury pupae and prevent adult emergence.
• Crop rotation to break the pest life cycle.
• Timely application of systemic insecticides if pest population density exceeds the economic threshold.