Rough weevil

The rough weevil (Brachycerus muricatus) is a member of the Curculionidae family within the order Coleoptera. This species is recognized as an agricultural pest that specializes in damaging specific bulbous plants, posing a notable threat to onion and garlic cultivation in its native range.

The primary hosts of this weevil are plants from the Amaryllidaceae family. The damage is caused by both adults, which feed on leaves and stems, and larvae, which tunnel into the bulbs. This feeding behavior causes systemic stress to the plants, often leading to secondary infections that accelerate decay.

Regarding its biology, the species typically completes one generation per year. Adults overwinter in the soil or under debris. With the arrival of spring, they emerge to feed and reproduce. Females lay their eggs in close proximity to the bulbs, allowing the emerging larvae to immediately begin burrowing into the host tissue for food.

The severity of the infestation is marked by the destruction of the bulb's structural integrity. Infested plants exhibit stunted growth, chlorosis, and wilting. In severe cases, particularly in intensive farming environments where crop rotation is neglected, the population of Brachycerus muricatus can lead to total crop failure.

Integrated pest management strategies are recommended to mitigate damage:

• Rigorous crop rotation, ensuring bulbous crops are not planted in the same soil for at least three to four years.
• Deep autumn plowing to expose overwintering adults to adverse conditions and predators.
• Removal and destruction of infested plant remnants post-harvest.
• Judicious use of chemical insecticides timed with the peak adult activity, following local agricultural guidelines.