Mallow weevil

Systematic position. The mallow weevil (Apion radiolus) belongs to the order Coleoptera, within the family Apionidae. It is a small snout beetle that has evolved to feed specifically on plants belonging to the Malvaceae family.

Crops damaged. This pest primarily targets species of mallow (Malva), hollyhock (Alcea), and hibiscus. It is particularly problematic in seed production fields where the larvae feed on developing seeds, compromising the reproductive capacity of the plants.

Biology and life cycle. Adults hibernate in soil debris or under leaf litter during the winter. In the spring, they emerge and begin feeding on succulent foliage. Females deposit eggs inside the buds or ovaries of the host plant. The larvae develop inside the seeds or stems, where they eventually pupate, completing their life cycle within the host tissue over several weeks.

Nature of damage. Larval feeding inside the seeds is the most damaging phase, often leading to the complete destruction of the seed crop. Adult weevils leave small, characteristic round holes in the leaves, known as shot-holing. Heavy infestations can lead to flower bud drop and reduced plant vigor, impacting both the ornamental value and seed yields.

Control measures. Integrated pest management should start with good sanitation, such as removing and burning plant debris after the harvest to eliminate hibernation sites. Controlling wild mallow weeds around the fields helps reduce local populations. In commercial settings, systemic insecticides applied during the early bud formation stage provide effective control of adult weevils before oviposition occurs.