Aquatic Plant Control Research Program. Rearing, Storing, and Efficacy Studies on Arzama densa for Release Programs against Waterhyacinth

摘要

This research was conducted to develop mass rearing and dispersal techniques for large-scale releases of Arzama densa as a biological agent for the management of waterhyacinth. Life history information on A. densa was obtained from field observations of natural populations and from laboratory studies. Various artificial diets and insect storage techniques were tested for rearing and synchronizing life stages of A. densa in release programs. The life history studies showed that natural enemies greatly reduce field populations of A. densa. Augmentation would likely be more effective in July/August or spring when parasite/predator populations are low. Nine consecutive laboratory generations of A. densa were successfully reared on an artificial diet that included a water extract of waterhyacinth. Storage of larvae at 8 C permitted synchronization of releases with little mortality. It was found that larvae can be successfully dispersed in segments of waterhyacinth petioles, but this method is labor-intensive. Arzama densa at a rate of one third instar larva/two plants successfully controlled waterhyacinth in artificial pools.