Rhubarb curculio

Systematic position. Lixus concavus belongs to the order Coleoptera and the family Curculionidae. It is commonly referred to as the rhubarb curculio and is recognized as a significant pest in both small-scale gardens and commercial rhubarb plantations.

Host plants and damage. The primary host for this beetle is rhubarb. Adult beetles feed on the leaves and stems, causing visible puncture marks. However, the most severe damage is caused by the larvae, which bore into the stems, creating tunnels that weaken the plant's structural integrity and facilitate the entry of fungal or bacterial pathogens.

Biology and life cycle. The life cycle involves egg, larva, pupa, and adult stages. Females insert eggs into the stems of the host plant. The larvae hatch and tunnel downwards through the stalks, feeding on the inner tissues. Adult beetles overwinter in debris or soil near the host plants, emerging in the spring to begin the cycle anew.

Character of damage. Infested plants typically exhibit oozing sap at the sites where females laid eggs or where larvae have tunneled. The stalks become discolored, brittle, and often rot due to secondary infections. Severe infestations can significantly reduce plant vigor and crop yield, making the stems unsuitable for consumption.

• Hand-picking and destroying adult beetles whenever they are sighted.
• Regularly inspecting stalks for signs of egg-laying punctures and removing them.
• Eliminating nearby wild host plants like dock or thistle.
• Maintaining soil health and removing debris around the garden in late autumn.
• Using physical barriers or targeted insecticide treatments if infestations are heavy.