pg . 78
NQ DRY TROPICS WEED FREE
SALVINIA
Salvinia molesta
SALVINIA
WATER WEEDS
DESCRIPTION
This is a perennial , free floating aquatic fern .
Leaves are small , narrow , spongy , bright green and oval in pairs along the stem . The surface is covered with long , stiff , hairs . When the plant matures the leaves become thick and fold at the midrib . Young leaves are oval , about 1 centimetre wide and lie flat on the water surface .
Roots trail from each pair of young leaves . As it matures , the roots resemble wet hair . Trailing stems with small , hairy spore capsules may also be found in the roots of mature plants .
Flowers are not produced by this weed , reproducing only by vegetative means .
Habitat it prefers slow moving streams or still water ponds with high nutrient levels and water temperatures around 20 to 30 ˚C .
Weed characteristics it can rapidly form mats that cover water storages , affecting water quality and flow , wildlife , irrigation , stock feeding , and recreational activities . The mats also create a haven for mosquitoes .
Dispersal under optimal conditions , it can double in size every two to three days .
BIOSECURITY MATTER
Restricted . This species is Category 3 Restricted matter under Queensland Legislation . This species is also listed a Weed of National Significance ( WONS )
HOW TO ACT
Prevention is the best control method . Early detection and rapid response will provide the best chance of control . Mechanical or hand removal of infestations is recommended with ongoing monitoring and follow up required . Biological control agent is highly effective when plant is actively growing . Apply herbicide strictly as per label recommendations .