Syphraea uberabensis (Coleoptera: Chrysomelidae) potential agent for biological control of Tibouchina herbacea (Melastomataceae) in the archipelago of Hawaii, USA

摘要

Biological invasions are one of the major threats to Hawaii's biodiversity. Herbacious glory tree, Tibouchina herbacea Cogn. (Melastomataceae), native to America, is regarded as one of the harmful plant species due to its fast growth, small wind dispersed seed and the absence of natural enemies. Since 1998, potential agents have been studied in Brazil for a classical biological control. This paper presents results from host range and impact tests conducted under field and laboratory conditions for Syphraea uberabensis Bechyne (Coleoptera: Chrysomelidae), which is indicated as having great potential as a control agent for T. herbacea. A detailed description of the adults of this insect has not been published, and we describe it in this paper. From agroup of 20 species of plants in ten families investigated, S. uberabensis fed only on the two species of Tibouchina demonstrating that Tibouchina supplies the physiological and biological needs of this insect. S. uberabensis completes its life cycle onthe leaves of T. herbacea and does not attack other plant parts. During summer months, the life cycle is completed in approximately 35 days, lengthening to 80 days in the cooler months. The main impact to the plant was caused by the third-instar larvae and adults, and the damage can kill plants in less than 2 weeks. In laboratory conditions, 25% of leaf damage caused leaf death and leaf drop. A batch of S. uberabensis was sent to the Quarantine Service of USD A in Hawaii in 2005 where further host-specificity tests are being conducted.