Status of Biological Control of Waterlettuce in Louisiana and Texas Using Insects

摘要

A series of surveys were conducted in southeastern Louisiana during the springand summer of 1990 to characterize the assemblage of herbivorous insects impacting waterlettuce. These surveys were considered an important first step prior to the release of Neohydronomous affinis in Louisiana, an exotic weevil imported to the United States for the management of waterlettuce. The two most commonly encountered herbivorous insects were the two polyphagous lepidopteran species, Samea multiplicalis and Synclita obliteralis. Other herbivorous insect species collected included Draeculacephla inscripta (leafhopper) and Rhopalosiphum nymphaeae (aphid). While these species apparently inflict minimal plant damage they may be important for their role in disease transmission. Neohydronomous affinis was also collected from several sites within a 50-mile circle from Lake Verret to east of Lake Beouf. The collection of N. affinis was surprising since the closest release of N. affinis was in Gainsville, FL, more than 500 miles away. Populations of N. affinis are persisting as indicated by relatively high levels occurring for two growing seasons. Explanations for the presence of N. affinis in southeastern Louisiana are unknown. It is probable that it was accidently released from infested plants brought from Florida release areas....Aquatic plant control, Biocontrol, Waterlettuce.