Cycad weevil

Systematic position: Rhopalotria dimidiata is a beetle species belonging to the order Coleoptera and the family Curculionidae. It is a highly specialized herbivore that has evolved alongside cycad plants. Its biology is strictly tied to the life cycle of its specific host plants, making it an obligate associate of the Cycadales order.

Host plants: This pest primarily affects cycads, specifically members of the genus Zamia, such as Zamia integrifolia. It is a major concern for botanical gardens, private collections, and nurseries that specialize in rare and ornamental cycad species, as it targets the critical reproductive structures of these plants.

Biology and life cycle: The life cycle of Rhopalotria dimidiata is centered around the strobilus (cone) of the host plant. Adult beetles are attracted to the cones for feeding and mating. Eggs are deposited inside the soft tissue of the cones, where larvae emerge and begin feeding internally. This internal feeding protects the larvae from external environmental factors and predators during their development.

Nature of damage and impact: Larval feeding causes significant structural damage to the cones, leading to the destruction of sporophylls and developing seeds. Symptoms of infestation include wilting, browning, and premature disintegration of the cones. The resulting economic and ecological loss is substantial, as the pest can completely prevent sexual reproduction in host plants, leading to the loss of viable seeds.

• Frequent monitoring of cycad cones during the reproductive phase.
• Removal and immediate destruction of infested cones to reduce the pest population.
• Application of systemic insecticides that can penetrate the cone tissues where larvae feed.
• Use of pheromone traps to monitor and manage adult populations in greenhouse settings.
• Implementation of strict quarantine protocols for incoming plant specimens to prevent the introduction of this pest.