Impact of environmental manipulation for Anopheles pseudopunctipennis Theobald control on aquatic insect communities in southern Mexico.

Extraction of filamentous algae from river pools is highly effective for the control of Anophelespseudopunctipennis in southern Mexico. We determined the magnitude of changes to the aquatic insect community following single annual perturbations performed over two years. In 2001, algae were manually removed from all the pools in a 3 km long section of the River Coatán, Mexico, while an adjacent section was left as an untreated control. In 2002, the treatments of both zones were switched and algal extraction was repeated. The abundance of An. pseudopunctipennis larvae + pupae was dramatically reduced by this treatment and remained depressed for two to three months. A total of 11,922 aquatic insects from ten orders, 40 families, and 95 genera were collected in monthly samples taken over five months of each year. Algal extraction did not reduce the overall abundance of aquatic insects in river pools, but a greater abundance and a greater richness of taxa were observed in 2002 compared to the previous year. This was associated with reduced precipitation and river discharge in 2002 compared to 2001. Shannon diversity index values were significantly depressed following algal extraction for a period of three months, in both years, before returning to values similar to those of the control zone. However, differences between years were greater than differences between treatments within a particular year. When insects were classified by functional feeding group (FFG), no significant differences were detected in FFG densities between extraction and control zones over time in either year of the study. Similarly, percent model affinity index values were classified as "not impacted" by the extraction process. Discriminant function analysis identified two orders of insects (Diptera and Odonata), water temperature, dissolved oxygen and conductivity, and river volume (depth, width, and discharge) as being of significant value in defining control and treatment groups in both years. We conclude that habitat manipulation represents an effective and environmentally benign strategy for control of An. pseduopunctipennis. Variation in precipitation and river discharge between years was much more important in determining aquatic insect community composition than variation generated by the filamentous algal extraction treatment.

Mass rearing and egg release of Buenoa scimitra Bare as biocontrol of larval Culex quinquefasciatus.

Backswimmers have been recognized as the most promising predators of mosquito larvae. The aim of this investigation was to study mass rearing and egg release of Buenoa scimitra for the biological control of Culex quinquefasciatus Say. Among the most important results were that production of backswimmer eggs occurred for 263 days, and also that eggs were released in artificial containers with production of new individuals until the adult stage was obtained. In addition, a statistically significant reduction in mosquito larval density was observed on some sampling dates.

Mosquito vector control and biology in Latin America--an eleventh symposium.

The 11th annual Latin American symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 67th Annual Meeting in Dallas, TX, in February 2001. The principal objective, as for the previous 10 symposia, was to promote participation in the AMCA by vector control specialists, public health workers, and academicians from Latin America. This publication includes summaries of 45 presentations that were given orally in Spanish or presented as posters by participants from 8 countries in Latin America. Topics addressed in the symposium included results from chemical and biological control programs and studies; studies of insecticide resistance; and population genetics, molecular, ecological, and behavioral studies of vectors of dengue (Aedes aegypti), malaria (Anopheles albimanus and Anopheles aquasalis), leishmaniasis (Lutzomyia), murine typhus, and Chagas' disease (Triatoma). Related topics included biology and control of Rhodnius, scorpions, Loxosceles spp., Chironomus plumosus, and Musca domestica.

Use of Bactimos briquets (B.t.i. formulation) combined with the backswimmer Notonecta irrorata (Hemiptera:Notonectidae) for control of mosquito larvae.

The efficacies of Bacillus thuringiensis var. israelensis (Bactimos briquets) and the backswimmer Notonecta irrorata were evaluated both individually and in combination to control mosquito larvae in plastic containers in Monterrey, Mexico. The combined strategy proved to be the most effective one.