Water hyacinth (Eichhornia crassipes) is a perennial plant of the Pontederiaceae family. Found naturally in tropical and subtropical regions, water hyacinth was introduced to the United States in 1884. Water hyacinth quickly attained weed status, invading rivers, canals, ponds and lakes. Water hyacinth has both anchored and free-floating varieties.
Both floating and anchored water hyacinth varieties have glossy green, round leaves that can reach up to 10 inches across. Both water hyacinth species produce large pale lilac to blue-purple flowers with distinctive yellow spots.
Water hyacinth plants are susceptible to several leaf spot disease, primarily those caused by the Myrothecium roridum and the Cercospora piaropi pathogens.
The Myrothecium roridum pathogen causes narrow bands to form from the infection site to the tip of the leaves. Cercospora piaropi causes brown spots to form around the infection site on the leaves.
Water hyacinth are vulnerable to attacks from weeveils (Neochetina eichhorniae), pyralid moths (Niphograpta albiguttalis) and mites (Orthogalumna terebrantis).
The weevils, moths and mites are often purposely released in order to naturally control the water hyacinth weed. These biocontrol agents generally take between 2 to 6 years to effectively control water hyacinth growth.