STUDIES FOR A SUSTAINABLE MANAGEMENT OF SCYPHOPHORUS ACUPUNCTATUS (COLEOPTERA, DRYOPHTHORIDAE) AT THE HANBURY BOTANIC GARDENS

Abstract

Scyphophorus acupunctatus Gyllenhal, 1838 Coleoptera: Dryophthoridae, the agave weevil, is an exotic species native to Central America that is now found on five continents. This species is parasite of several species of Asparagaceae (Agavoideae and Nolinoideae) and is the major pest of wild and cultivated Agaves. Scyphophorus acupunctatus is a threat to Agave and related genera collections in botanic gardens, as well as ornamental plants in urban areas, in the Mediterranean Basin.

In 2018 S. acupunctatus was first detected in Hanbury Botanic Gardens, La Mortola (Ventimiglia, IM - Italy); since then, the parasite has killed several specimens of Agave and related genera, causing significant damage to the botanic collection.

The study, here presented, was carried out using pheromone and agave baited traps in order to assess the damage caused to the collection and to evaluate the influence of temperature, relative humidity, and rainfall on the activity of S. acupunctatus. The effect of the treatments against the parasite was also evaluated.

The highest level of S. acupunctatus activity was recorded in spring (moderate rainfall (51.8 mm), a temperature 22° - 26°C, relative humidity > 60%). Pheromone traps were more effective than baited traps. The monitoring data following the treatments revealed a drop in captures of the species, suggesting a lethal effect of the applied products. The level of damage assigned to host plants revealed the presence of at least one infested plant in 12 of the 14 monitored areas of Hanbury Botanic Gardens’ and 1/4 of the individuals in the collection show an infestation symptom.