Current Research

Biological Control of Mosquitoes

Worldwide, the use of pesticides has increased more than ten-fold since the 1950s (Driesche and Bellows 1996). Many pesticides have been effective in controlling the target pests, but there are problems associated with their widespread use including' pest control failures, development of resistant insecticide resistance, elimination of populations of beneficial organisms, contamination of the environment, damage to human health, and often very high costs. Although pesticides will be with us for the foreseeable future, an integrated approach to pest management is now considered essential, particularly in view of the challenges facing future generations in terms of human health and the world's food and energy supplies. Biological control is a fundamental part of integrated pest management programs.

The cyclopoid copepod Macrocyclops albidus (Jurine) is being tested tested for biological control of mosquitoes in laboratory microcosms, in controlled field conditions, and in field experiment using discarded tires. This copepod species is a promising candidate for control of mosquito larvae because it is a widespread and highly effective predator that is capable of establishing and maintaining populations under a wide variety of field conditions. Additionally, M. albidus is relatively easy to culture, maintain, and deliver to the target areas. Future work will focus on performance testing of this and other species under different conditions and in different habitats.

Setting up a predation experiment in the FMEL "Roundhouse." Sampling a discarded tire for mosquito larvae and copepod predators. Observing copepod predation behavior.

Prediction of Arbovirus Vector Habitats in South Florida

Setting up oviposition traps
in a Dade County residential area.		  
This project builds upon preliminary research to investigate habitat factors that influence the spatial distribution of Aedes aegypti, Aedes albopictus, and Culex spp in South Florida, and to develop a set of easily measured habitat and geographic variables that can be used to predict the presence and abundance of these potential disease vectors. The major objective is to develop a set of easily measured habitat and geographic variables that can be used to predict the presence and abundance of potential arbovirus vectors.

We selected and sampled sites in Palm Beach, Miami-Dade, and Manatee counties that include urban, suburban, and rural settings. Mosquito abundance and production was monitored at these sites using oviposition traps for Aedes and Culex species. For each site a number of variables related to habitat, weather, and human proximity and density are being measured or are being extracted from existing data bases.

Various types of georeferenced maps are being deloped to illustrate relationships between mosquito production and the other variable measured. At this point, we have obtained and georeferenced aerial imagery for Miami-Dade and Palm Beach Counties, have located our sample locations in the geroreferenced images , and are in the process of digitizing habitat features of each site. Geographic and conventional statistical analyses will be utilized to validate relationships and to generate predictive models of mosquito production and abundance in the different habitats.

Biology and Control of Mosquitoes in Nutrient-Rich Aquatic Systems

Constructed treatment wetlands (CTWs) have been established for treating stormwater and wastewater at numerous sites in Florida. These aquatic systems provide efficient and economical procedures for improving water quality, recycling and conserving water, and providing wildlife habitats. Over the next few years, there will probably be a large increase in the number of CTW systems in Florida as communities seek solutions to major water supply and water quality problems. Unfortunately, constructed wetlands may provide suitable habitats for pestiferous and disease vectoring mosquitoes, especially if they receive a nutrient-rich influent. Culex mosquitoes, the primary vectors of Saint Louis Encephalitis (SLE) and West Nile (WN) viruses in Florida, thrive under nutrient-rich conditions. CTW systems also may produce large numbers of pest mosquitoes (Mansonia and Coquillettidia spp.) if certain types of aquatic plants invade CTWs.

Sampling floating vegetation
in a constructed wetland.
Objectives:

Mosquito Production in Stormwater Catch Basins and Drains.

To comply with state and federal regulations on stormwater runoff from urban and suburban areas, many communities have or are in the process of implementing new programs to reduce the adverse impact of stormwater runoff on streams, rivers, lakes and estuaries. Compliance is being achieved generally by placing a greater reliance on the retention of stormwater onsite, which invariably results in catch basins and drains holding water more frequently – a condition that often enhances mosquito production. There are, however, many different types of stormwater catch basins and drains located in a variety of habitats. Certain design/construction features and site locations may make some stormwater catch basins and underground drains less likely to generate a severe mosquito problem than others.

The primary goal of this research proposal is the acquisition of information needed for designing and maintaining stormwater catch basins and drains, which are less likely to generate mosquito problems.

We plan to test the following hypotheses:

Field studies will be conducted in Monroe, Indian River and St. Lucie Counties we plan to sample for mosquito larvae and pupae without removing grates by using a flexible tube attached to portable, self-priming hand pump. Each stormwater catch basin/drain will be sampled twice a month from February to November.

Microalgal allelopathic products for mosquito control

Entomoneis sp.


Development of new biorational mosquitocides is critical nor only for mosquito and disease control, but also for protection of our natural resources. Many classes of marine algae produce allelochemicals and nearly all microalgae (> 0.2mm) examined have been shown to produce exudates. As far as we know, there have been no investigation of marine allelochemicals as inhibitors or biocides against mosquitoes. We propose to isolate strains of marine planktonic and benthic microalgae, characterize their identity, and examine their allelopathic activity against mosquito larvae. We are currently challenging mosquito larvae with allelopathic microalgae using log growth phase (active metabolism) and senescent phase aqueous extracts of microalgal material.

The following variables are being evaluated in treatment and control replicates as indicators of effects of algal extracts upon Aedes aegypti larvae:
Senescent and log-phase
discs ready for testing


The latter is being measured using a non-contact digital measurement system (Caltex) calibrated with a mm stage micrometer.

The proposed combination of experimental methods and statistical analysis should be able to detect any significant effect of the microalgal extracts upon the mosquito larvae. Direct effects on survival will be reflected in the LD:50 LD:90 analyses, whereas non-lethal effects upon life history should be evident from the pupation and emergence time data, emerging adult sex ratios and size data, and from the composite index of population performance.



Part of an experimental trial.