1.
Alternanthera
philoxeroides, commonly known as Alligator weed, is an immersed aquatic plant.
2.
Alligator weed is a Weed of National
Significance.
3.
It is regarded as one of the worst weeds
in Australia because of its invasiveness, potential for spread, and economic
and environmental impacts.
4.
It is an especially troublesome weed
because it invades both land and water, and is very hard to control.
5.
Alligator weed can grow with roots
embedded in the bank or on the bottom of shallow water bodies, or float freely
on the water surface.
6.
It spreads its leaves across the water
surface, forming dense mats.
7.
The long spreading stems are hollow,
helping it to float.
8.
The roots are thin and stringy, and trail
in the water from the joints between plant segments (the nodes).
9.
Alligatorweed is usually found growing in
water, it is also capable of growing in a variety of habitats including dry
land.
10. The
stems of alligator weed are long, branched and hollow with 2 leaves opposite
each other.
11. The
flowers grow from the axils of the leaves.
12. They
have five white sepals and appear as white balls.
13. Alligator weed
is found in ponds, lakes, streams, canals and irrigation ditches and can form
dense, sprawling mats.
14.
It originated in South
America, but has spread to many parts of the world and is considered an
invasive species in Australia, China, New Zealand, Thailand and the United
States.
15. When
alligator weed invades waterways it can reduce water flow and quality by
preventing light penetration and oxygenation of the water.
16. It
can also reduce water bird and fish activity and cause the death of fish and
native plants.
17. Alligator
weed mats create a favorable habitat for breeding mosquitoes.
18. Alligator
weed is also difficult to control.
19. Insects
have been released for the biological control of alligator weed.
20. The
most successful and widely used is Agasicles hygrophila commonly called the
alligator weed flea beetle; it has been released for biocontrol in Australia,
China, Thailand, New Zealand and the United States.
21. Amynothrips
andersoni, the alligator weed thrips, and Vogtia malloi, the alligator weed
stem borer, have also been released in the United States.
