Eichhornia crassipes, commonly known as Common Water Hyacinth, is an aquatic plant native to the Amazon basin, and is often considered a highly problematic invasive species outside its native range.
Description
Its habitat ranges from tropical desert to subtropical or warm temperate desert to rainforest zones. It tolerates annual precipitations of 8.2 dm to 27.0 dm (mean of 8 cases = 15.8 dm), annual temperatures from 21.1°C to 27.2°C (mean of 5 cases = 24.9°C), and its pH tolerance is estimated at 5.0 to 7.5. It does not tolerate water temperatures >34°C. Leaves are killed by frost and salt water, the latter trait being used to kill some of it by floating rafts of the cut weed to the sea. Water hyacinths do not grow when the average salinity is greater than 15% that of sea water. In brackish water, its leaves show epinasty and chlorosis, and eventually die.
Because of E. crassipes invasiveness, several biological control agents have been released to control it, including two weevils, Neochetina bruchi Hustache (Coleoptera: Curculionidae) and Neochetina eichhorniae Warner (Coleoptera: Curculionidae), and the moth Niphograpta albiguttalis (Warren) (Lepidoptera: Pyralidae).Neochetina eichhorniae causes "a substantial reduction in water hyacinth production" (in Louisiana); it reduces plant height, weight, root length, and makes the plant produce fewer daughter plants. N. eichhorniae was introduced from Argentina to Florida in 1972.
Azotobacter chroococcum, an N-fixing bacteria, is probably concentrated around the bases of the petioles. But the bacteria do not fix nitrogen unless the plant is suffering extreme N-deficiency.
Fresh plants contain prickly crystals. This plant is reported to contain HCN, alkaloid, and triterpenoid, and may induce itching.Plants sprayed with 2,4-D may accumulate lethal doses of nitrates,as well as various other nocive elements in polluted environments. See further down.
Because of E. crassipes invasiveness, several biological control agents have been released to control it, including two weevils, Neochetina bruchi Hustache (Coleoptera: Curculionidae) and Neochetina eichhorniae Warner (Coleoptera: Curculionidae), and the moth Niphograpta albiguttalis (Warren) (Lepidoptera: Pyralidae).Neochetina eichhorniae causes "a substantial reduction in water hyacinth production" (in Louisiana); it reduces plant height, weight, root length, and makes the plant produce fewer daughter plants. N. eichhorniae was introduced from Argentina to Florida in 1972.
Azotobacter chroococcum, an N-fixing bacteria, is probably concentrated around the bases of the petioles. But the bacteria do not fix nitrogen unless the plant is suffering extreme N-deficiency.
Fresh plants contain prickly crystals. This plant is reported to contain HCN, alkaloid, and triterpenoid, and may induce itching.Plants sprayed with 2,4-D may accumulate lethal doses of nitrates,as well as various other nocive elements in polluted environments. See further down.
