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Decaying experiments of four major aquatic macrophyte detritus, namely cattail ( Typha orientalis ), water lettuce ( Pistia stratiotes ), hydrilla ( Hydrilla verticillata ) and maidencane ( Panicum hemitomon ), were conducted using the litterbag technique in the stormwater detention pond of South Florida, USA. Dry weight and chemical composition of remaining biomass were dynamically determined during the 185-day decay experiment. The results showed that decomposition rates ( k ), and the derived turnover ( t 50% and t 95% ) were species specific. The k values decreased in the order of hydrilla (0.0123 g day −1 ) > water lettuce (0.0082 g day −1 ) > maidencane (0.0049 g day −1 ) > cattail (0.0031 g day −1 ), whereas t 50% and t 95% varied in the reverse way. Biomass properties including concentrations of C, N, P, lignin, cellulose, hemicellulose, and the ratios of C/N, C/P, N/P and lignin/N affected decaying rate of the studied aquatic plants. The dry mass loss and concentrations of C, N, P, lead (Pb), chromium (Cr), copper (Cu), manganese (Mn), zinc (Zn), lignin, cellulose, hemicellulose and ratios C/N, C/P, N/P and Lignin/N of plant detritus were significantly affected by species, decaying time, and their interactions. However, the influence of species differences was greater than that of decaying time on those indexes. The estimated amounts (kg) of nutrients and metals released based on k values for the waterways of the IRL basin (water surface area 15.6 km 2 ) were N 126.85 × 10 3 , P 8.89 × 10 3 , Zn 408.20, Pb 97.95, Cr 128.99, Mn 313.03, and Cu 82.40. Water lettuce contributed most, accounting for 52.13% N, 56.81% P, 74.95% Zn, 59.58% Pb, and 74.65% Mn, followed by hydrilla, cattail and maidencane. For Cr and Cu, cattail had the greatest contribution of 65.77% and 54.15%, respectively, followed by water lettuce, hydrilla and maidencane. [ABSTRACT FROM AUTHOR]

Culex ( Melanoconion ) panocossa is a suspected vector of Venezuelan equine encephalitis virus in Central America. Prior to this report, Cx . panocossa was known from Central America (Belize, Costa Rica, El Salvador, Guatemala, southern Mexico, Panama), northern South America (Colombia, Venezuela) and the Greater Antilles (Cuba and Jamaica). Larvae (n = 5) and adults (n = 4286) of Cx . panocossa were collected at two locations near Homestead, FL, which indicates substantial established populations of this probable vector species in the continental US. Since larvae of Cx. panocossa are associated with Pistia spp. (water lettuce), the distribution of this mosquito is likely to expand in Florida, where water lettuce is a major invasive plant in freshwater ecosystems. The putative establishment of Cx . panocossa in Florida is of significant concern from a public health perspective, as its proliferation in developed areas could link historically sylvatic transmission foci of Everglades virus with populated centers such as the greater Miami Metropolitan area. [ABSTRACT FROM AUTHOR]

The article evaluates the effectiveness and potential of water lettuce, Pistia stratiotes, in removing nutrients from stormwater detention ponds in Saint Lucie Estuary, Florida. Study shows improved water quality in the ponds as evidenced by decreases in suspended solids, water turbidity, and nutrient concentrations. It suggests that water lettuce can remove nitrogen (N) and phosphorus (P) from eutrophic stormwaters and help improve other water quality properties.

We released nearly 332 000 Spodoptera pectinicornis individuals for biological control of the floating aquatic weed Pistia stratiotes (waterlettuce) at 22 sites in Florida during December 1990-December 1997. Predation (by boat-tailed grackles, fire ants, and spiders) and Allee effects (resulting from rapid dispersal of adults) prevented populations from persisting during early attempts. These efforts consisted of small releases at multiple sites, with no nurturing of the introduced populations. Modification of our initial approach resulted in a series of release strategies that consisted of multiple releases at fewer sites and employed progressively more intensive nurturing of the introduced populations. The most successful strategy incorporated: (i) cages to restrict adult dispersal and exclude flying predators; (ii) plant-free zones around the cages to exclude crawling predators; (iii) enhancement of the nutritional quality of waterlettuce in the cages; and (iv) frequent inoculation of the cages with laboratory-reared insects. Use of this strategy resulted in several provisionally-established S. pectinicornis populations, numbering as much as 23.5 S. pectinicornis individuals m[sup -2], and produced up to seven post-release generations. Unfortunately, all of these incipient populations declined until S. pectinicornis was undetectable. We conclude that field populations of this moth no longer persist in Florida, and offer an introspective assessment of how this project might have been improved. [ABSTRACT FROM AUTHOR]

Mosquitoes use many cues to assess whether a habitat is conducive for reproduction, possibly including the presence of stimuli from aquatic macrophytes. The effect of water infusions of water hyacinth (Eichhornia crassipes), water lettuce (Pista stratioles), parrotfeather (Myriophyllum aquaticum), and water pennywort (Hydrocotyle umbellata) on mosquito oviposition and attraction was investigated. Gravid Culex quinquefasciatus deposited significantly more egg rafts in water hyacinth, water lettuce, or Bermuda hay (positive control) infusions compared to water, while water pennywort and parrotfeather infusions did not differ from water. In-flight attraction responses of Cx. quinquefasciatus, Aedes aegypti, and Anopheles quadrimaculatus were evaluated. The strongest attraction of gravid Cx. quinquefasciatus and Ae. aegypti occurred in the presence of volatiles from infusions of water hyacinth and water lettuce, which were equal in attractiveness to hay infusion. Water pennywort and parrotfeather infusions were not attractive. Gravid An. quadrimaculatus were not attracted to aquatic plant volatiles. The results suggest that water hyacinth and water lettuce emit volatile chemicals that attract two of three mosquito species tested and stimulate oviposition by Cx. quinquefasciatus, demonstrating that the level of attraction of aquatic plant volatiles varies among species in ways that may have relevance to bait-based detection and control methods., (© 2018 The Society for Vector Ecology.)