Eurasian Watermilfoil Control PDF Download

This report presents the results of the evaluation of two species of insects for the biological control of Eurasian watermilfoil (Myriophyllum spicatum L.). One of the species is a native weevil, Litodactylus leucogaster (Marsh.), which attacks the flower spikes, and the other is an accidentally introduced European moth, Acentria nivea (Oliver), whose larvae feed on the leaves and stems. The biology of L. leucogaster was studied in detail and host-specificity tests were conducted with adults and larvae. Since it was determined to be specific to watermilfoils, it was released at Crystal River, Florida, on 22 August 1979. Two adults were captured at Crystal River in November indicating possible establishment. The pyralid moth, A. nivea, was difficult to rear in the laboratory. Since the females were active only one night, successful matings were rare in the small colony. Larval production was best in containers that were minimally disturbed. the larvae required water temperatures below 22 C for development though they could survive short periods at higher temperatures. The larvae were not specific to milfoil; however, A. nivea may still be of interest as a member of a complex of species which attack milfoil. (Author).