Alfalfa curculio

Systematic position. This pest belongs to the order Coleoptera and the family Curculionidae. Sitona humeralis is recognized as a significant agricultural pest that specifically targets legume crops, particularly in regions where alfalfa production is intensive and monoculture practices are common.

Crops damaged. The primary host plant for this species is alfalfa (lucerne). However, under high population pressure or lack of primary hosts, it can also infest other leguminous plants, causing significant economic damage to both fodder crops and seed-producing fields.

Biology and life cycle. Adults hibernate in the soil or within plant debris during the winter. As spring temperatures rise, the beetles emerge to feed on foliage. Mating occurs shortly after, followed by egg-laying in the soil near the root zone. Once hatched, the larvae migrate downwards to feed on the root nodules.

Damage and economic importance. Adults produce characteristic scalloped edges on the leaves, which is a key diagnostic symptom. The larvae are considered the most destructive stage, as they feed on the nitrogen-fixing root nodules. This feeding habit leads to reduced plant vigor, poor crop establishment, and lowered protein content in the foliage.

Control measures. Integrated pest management strategies include crop rotation, the use of resistant varieties, and timely cultivation to disrupt the life cycle. In severe infestations, the application of registered insecticides is recommended, targeting the adult stage before they complete their egg-laying period to prevent larval damage.