Treatments for giant salvinia are similar to those for duckweed.
SONAR is very effective on Salvinia, particularly for ponds with lots of nooks and crannies (or shoreline brush/weeds). Salvinia may be growing, yet obscured in such areas. SONAR permeates the entire pond, so there's no refuge in which the Salvinia may hide.
REWARD is also effective, but EACH plant MUST be contacted if it is to be controlled. Also, unlike duckweed, salvinia has a densely-haired leaf surface. Therefore, additional surfactant is usually needed in order to penetrate the leaf-hairs. Otherwise, spray droplets will never make contact with the leaf surface and the treatment will be completely inaffective.
Dave - though considered an aquatic plant, we have found many situations (ie.
Lake Conroe ) where Salvinia can survive for extended periods of time in muddy/moist areas without any surface water - just waiting for the next water-level rise (as with duckweed).
Every coastal state pond-owner needs to be aware of this particular plant. Many aquatic plants may occasionally represent a minor to moderate nusiance. However, Salvinia frequently causes major problems whenever it is introduced to a water body (whether naturally, accidently, or intentionally).
This photo shows the typical results of Salvinia growing in a small pond (photo taken 4 months after the owner unwittingly tossed in a double-handfull of Salvinia because he thought it looked "neat"). No fish survived....
Tomball, TX
