When was hydrilla introduced

See the current distribution of hydrilla in the United States. The plant is a submerged, rooted perennial with long stems up to 30 feet in length that branch at the surface and form dense mats. Small white flowers grow above the water line on stalks. Leaf midribs are often reddish with one or more sharp spines. The most reliable way to identify hydrilla is to look for small, white to yellowish, potato-like tubers attached to the roots.

Hydrilla can be found infesting freshwater lakes, ponds, rivers, impoundments and canals. It is extremely hardy and can grow in many conditions, including low light levels and poor nutrient areas. Hydrilla grows aggressively, up to a foot a day, and forms dense mats of vegetation that crowd out other plants.

The dense mats often cause stagnant water conditions which provide breeding grounds for mosquitoes and provide poor habitat for diverse fish and other wildlife populations. Anglers may find a decrease in the size and quantity of fish in waterbodies where hydrilla is present.

Hydrilla once was used as an aquarium plant, and has become a weed of economic importance. Hydrilla verticillata is the only species in this genus. Leaves : submersed; in whorls of 3 to 8, mm 0. Stems : slender with much branching and up to Flowers : female flowers solitary, on long stalks, with three sepals and three petals, each about 4 mm 0. Other characteristics : two types of special vegetative propagules: turions - fattened leaf buds at stem nodes, green, about 1.

This submersed plant native to Africa and Southeast Asia is a major aquatic weed throughout most of the world's warmer climates. Hydrilla was introduced into Florida in the early s and by the early s occupied more than , acres of public lakes and rivers.

Intensive interagency management has reduced the above ground portions of hydrilla to under 50, acres. Each stem on a Hydrilla plant can grow inches per day. Therefore, when hydrilla invades water bodies, ecologically-important native submersed plants such as pondweeds Potamogeton spp. Dense infestations can alter water chemistry and dissolved oxygen levels. Avoid introducing hydrilla into water bodies.

Use best practices to prevent introduction by cleaning boat trailers, propellors, diver gear and live bait wells. Transporting plant fragments on boats, trailers, and in livewells is the main source of introduction into new lakes and rivers.

Do not use hydrilla in aquariums or ornamental ponds. Cofrancesco, and J. Hydrilla verticillata L. Castanea Access Washington. Hydrilla verticillata discovered in the Crystal River in south Florida in Raghavan Charudattan, University of Florida. Range map. Hydrilla stems. Photo: not known. Hydrilla verticillata. Allison Fox,