Twenty-four-spot ladybird

The twenty-four-spot ladybird (Subcoccinella vigintiquatuorpunctata) is a unique member of the Coccinellidae family that exhibits herbivorous habits. Unlike the majority of ladybirds known as beneficial predators, this beetle from the order Coleoptera feeds strictly on plant tissue, which classifies it as a significant pest in agricultural settings.

This beetle primarily attacks leguminous crops, with alfalfa and clover being the most vulnerable targets. It is also known to infest sainfoin and occasionally vegetables. The damage is distributed across various regions where perennial forage grasses are cultivated, leading to notable losses in biomass productivity.

The life cycle begins with the overwintering of adults in crop debris, hedge rows, or leaf litter. Upon the arrival of spring, they emerge and initiate feeding on young tender leaves. Females deposit eggs in clusters on the underside of host leaves. The larvae undergo several developmental stages before pupating, often causing more damage than the adults.

The damage is characterized by the skeletonization of leaves. Both adults and larvae graze on the epidermis and parenchyma, leaving the vein network intact. This activity weakens the plant significantly, causing leaves to wither prematurely. High populations can cause entire stands of forage crops to appear bleached or scorched.

Effective management strategies include:

• Early harvesting of alfalfa to remove eggs and larvae before they mature.
• Strict field sanitation, including the removal of weeds and crop residues where beetles hibernate.
• Monitoring pest density during the vegetative growth phase.
• Targeted application of insecticides if the population exceeds economic threshold levels.