Effects of pH on Growth of Salvinia molesta Mitchell

Growth of giant salvinia ( Salvinia molesta Mitchell) under different pH regimes was examined at the Lewisville Aquatic Ecosystem Research Facility (LAERF) in Lewisville, Texas.(PDF has 5 pages.)

Natural Suppression of the Aquatic Weed Salvinia molesta D.S. Mitchell, by Two Previously Unreported Fungal Pathogens

Salvinia molesta D. S. Mitchell (Salviniaceae), variously called giant salvinia, water fern or African payal, is a vegetatively reproducing, perennial, free-floating, aquatic weed, native to southeastern Brazil (Waterhouse and Norris 1987). It (hereafter called salvinia) is a very serious weed in most regions outside its native range (Harley and Mitchell 1981) including India. The purpose of this paper is to report on two fungal pathogens that were found to be the cause of a sudden decline in salvinia in Bangalore.(PDF has 4 pages.)

Contribution à l'étude de la croissance de la fougère aquatique Salvinia molesta (Mitchell), Salviniaceae

The growth of the primary and the tertiary forms of the water fern Salvinia molesta was studied during 60 days in 0.06 m2 glass containers containing fresh water. The growth of this plant as a function of time is exponential. The two forms have growth rates statistically identical. The main daily growth rate, expressed in number of leaves, is equal to 6.40% per day for primary forms and 5.90% per day for tertiary form, with doubling time of 10.78 + 1.08 days and 11.64 + 0.15 days.

Catalogue des ennemis naturels des macrophytes flottants Pistia stratiotes, Salvinia molesta et Eichhornia crassipes

We identified from bibliographical review and field observations fourty two species composed essentially of molluscs and insects. These animals attack floating plants such as E. crassipes, P. stratiotes and S. molesta. They indifferently consume or destroy the aquatic plants except N. bruchi, N. eichhorniae and S. albiguttalis which specifically attack E. crassipes. N. putchellus, L. guinaicus and P. africana graze preferably P. stratiotes; C. salviniae, C. singularis and P. acuminata consume only Salvinia molesta.

A new water weed, giant salvinia (Salvinia molesta), invades Lake Kyoga

Giant salvinia (Salvinia molesta) is an introduced invasive water weed in the tropics and subtropics It is a free floating weed that grows rapidly and forms extensive dense mats over still or slow moving waters.

Status of kariba weed (Salvinia molesta) infestation, its impacts and control options on Uganda’s water systems

Kariba weed (Salvinia molesta) is an invasive alien waterweed that was first recorded in Uganda in sheltered bays of Lake Kyoga in June 2013. This waterweed has become a common feature on Lake Kyoga and its associated rivers, streams and swamps, and has spread to other lakes notably Kwania and Albert in addition to Lake Kimira in Bugiri district.

Assessing Biological Control Damage of Giant Salvinia with Field Reflectance Measurements and Aerial Photography

A study was conducted on a small pond in southeast Texas to evaluate the potential for using remote sensing technology to assess feeding damage on giant salvinia ( Salvinia molesta Mitchell) by the salvinia weevil ( Cyrtobagous salviniae Calder and Sands). Field spectral measurements showed that moderately damaged and severely damaged plants had lower visible and near-infrared reflectance values than healthy plants. Healthy, moderately damaged, and severely damaged giant salvinia plants could be differentiated in an aerial color-infrared photograph of the study site. Computer analysis of the photograph showed that the three damage level classes could be quantified. (PDF has 5 pages.)

Tilapia for Biological Control of Giant Salvinia

In August 1999, giant salvinia ( Salvinia molesta Mitchell) was found along the lower Colorado River in irrigation drainages. To investigate the slow spread and apparent control of giant salvinia in this region, the herbivorous fish, tilapia (Oreochromis niloticus Trewavas), was examined as a biological control agent. The study was conducted in a 5,000-L recirculating system. (PDF contains 4 pages.)

Remote sensing of giant salvinia in Texas waterways

Giant salvinia (Salvinia molesta Mitchell) is an invasive aquatic fern that has been discovered at several locations in southeast Texas. Field reflectance measurements were made on two classes of giant salvinia [green giant salvinia (green foliage) and senesced giant salvinia (mixture of green and brown foliage)] and several associated species. Reflectance measurements showed that green giant salvinia could be best distinguished at the visible green wavelength, whereas senesced giant salvinia could generally be best separated at the near-infrared (NIR) wavelength. Green giant salvinia and senesced giant salvinia could be detected on color-infrared (CIR) aerial photographs where them had pink and grayish-pink or olive-green image responses, respectively. Both classes of giant salvinia could be distinguished in reflectance measurements made on multiple dates and at several locations in southeast Texas. Likewise, they could he detected in CIR photographs obtained on several dates and at widely separated locations. Computer analysis of a CIR photographic transparency showed that green giant salvinia and senesced giant salvinia populations could he quantified. An accuracy assessment performed on the classified image showed an overall accuracy of 87.0%.

Effect of Cattail (Typha domingensis) Extracts, Leachates, and Selected Phenolic Compounds on Rates of Oxygen Production by Salvinia (Salvinia minima)

Salvinia (Salvinia minima Willd.) is a water fern found in Florida waters, usually associated with Lemna and other small free-floating species. Due to its buoyancy and mat-forming abilities, it is spread by moving waters. In 1994, salvinia was reported to be present in 247 water bodies in the state (out of 451 surveyed public waters, Schardt 1997). It is a small, rapidly growing species that can become a nuisance due to its explosive growth rates and its ability to shade underwater life (Oliver 1993). Any efforts toward management of salvinia populations must consider that, in reasonable amounts, its presence is desirable since it plays an important role in the overall ecosystem balance. New management alternatives need to be explored besides the conventional herbicide treatments; for example, it has been shown that the growth of S. molesta can be inhibited by extracts of the tropical weed parthenium (Parthenium hysterophorus) and its purified toxin parthenin (Pande 1994, 1996). We believe that cattail, Typha spp. may be a candidate for control of S. minima infestations. Cattail is an aggressive aquatic plant, and has the ability to expand over areas that weren't previously occupied by other species (Gallardo et al. 1998a and references cited there). In South Florida, T. domingensis is a natural component of the Everglades ecosystem, but in many cases it has become the dominant marsh species, outcompeting other native plants. In Florida public waters, this cattail species is the most dominant emergent species of aquatic plants (Schardt 1997). Several factors enable it to accomplish opportunistic expansion, including size, growth habits, adaptability to changes in the surroundings, and the release of compounds that can prevent the growth and development of other species. We have been concerned in the past with the inhibitory effects of the T. domingensis extracts, and the phenolic compounds mentioned before, towards the growth and propagation of S. minima (Gallardo et al. 1998b). This investigation deals with the impact of cattail materials on the rates of oxygen production of salvinia, as determined through a series of Warburg experiments (Martin et al. 1987, Prindle and Martin 1996).

Les gasteropodes aquatiques associés aux plantes flottantes

The gasteropods sampling from roots system of floating plants Pistia striatiotes, Salvinia molesta, Salvinia nymphellula, Eichhornia crassipes, show that those biotopes are not azoic. We collected 18 species of gasteropods. The mapping of the species collected has been realized and permitted to identify three regions and three groups of gasteropods: 1 The gasteropods collected between 5° and 7° South; 2 The gasteropods collected between 8° and 10° North; 3 The widespread gasteropods. The species distribution according to latitude shows that 90% of species are found between 5° and 6° South, 65% between 6° and 7° South, 20% between 7° and 8°, 20% between 8° and 9° and 15% between 9° and 10° North.

Les macrophytes aquatiques des berges lagunaires

This synthetic article describes the composition and organization of vegetations colonizing the Ebrié lagoon banks and provides original data on the recent evolution of this association consecutively to the accidental introduction of 2 new species of floating macrophytes (Salvinia molesta and Eichhornia crassipes).