ABSTRACT
Although the search for and preliminary testing of new enemies of water hyacinth is continuing in South America, this chapter focuses on five promising species of arthropods. One of these arthropods is already present in the United States, apparently having entered this country along with water hyacinth. This species is an oribatid mite, Orthogalumna terebrantis Wall-work. A second arthropod, the bagoine weevil, Neoehetina bruchi Hustache, is also being studied in Argentina. This species is recorded from Guyana, Brazil, Uruguay, and Argentina, feeding only upon species of Pontederiaceae. The water hyacinth mite, Orthogahimna terebrantis, was completely specific to water hyacinth in laboratory tests. Adult mites are almost unable to feed on living plant tissue, and probably feed on decaying tissue within the old galleries of the nymphs, in injuries, or in the feeding spots of other insects and snails. In laboratory tests, adults survived longer on algae than on entire or injured leaves of water hyacinth.
