Insect survey of potential biological control agents of Myrica faya in the Azores and Madeira Islands, Portugal, 1988

Abstract

Myrica faya is an introduced shrub, or tree, recognized as one of the most potentially damaging and aggressive plants invading Hawaii's forests. In an effort to establish biological control of this plant, plant pathologists and entomologists visited the Azores and Madeira Islands of the North Atlantic where this plant is native, in the spring of 1984 and 1987, in a search for potential control agents. As a continuation of this survey, a fall visit to the Azores and Madeira was made by an entomologist in 1988. Results of this survey are discussed in this report. Fall was a poor time for observing insect activity on M. faya. On the Azores Islands, two weeks were spent intensively sampling 14 representative sites, 12 on the island of Pico. The fruit feeding caterpillar Carposina atlanticella and an unidentified twig mining caterpillar, two promising insects identified in earlier visits to Madeira, are not present in the Azores. Also no evidence was found for any insects attacking roots, wood, or seeds of M. faya. A large number of sucking insects were found, and based on previous surveys a complex of insects that attack the male flowers exists, both of these complexes deserve further study. The most promising insect from the Azores is the leaf-rolling caterpillar Phyllonorycter myricae, and a new colony was collected and returned to quarantine in Hawaii where it is undergoing studies. On Madeira both C. atlanticella and the twig mining caterpillar had been active earlier in the season, but by fall had begun winter diapause and could not be collected. A promising new insect, a leaf-mining caterpillar, was observed but attempts to collect and transport a colony to quarantine in Hawaii were unsuccessful. A major outcome of this visit was locating several entomologists on both the Azores and Madeira that expressed an interest in cooperating in future studies of Myrica faya insects.