RESUMEN
Larvicides that contain spinosad, a bacterial metabolite, are used to control mosquitoes in diverse aquatic habitats. These same habitats are home to other invertebrates, including Crustacea-fairy shrimp, isopods, and amphipods-and mollusks-fingernail clams and freshwater snails. A double-blind study evaluated the effects of Natular® G, a granular treatment containing spinosad, on spring Aedes spp. and nontarget invertebrates in vernal wetlands. Within 14 days after application, Natular G controlled larvae of spring Aedes by 53-84%, depending on species, but had no significant effects on numbers of fairy shrimp, fingernail clams, or freshwater snails. A second double-blind study evaluated effects on Coquillettidia perturbans and nontarget isopods and amphipods in cattail marshes. Treatment reduced emergence of Cq. perturbans by 25% but did not change numbers of isopods or amphipods. The 2 experiments indicate Natular G could be effective against spring Aedes in vernal wetlands, less so against Cq. perturbans in cattail marshes, and yet pose minimal risk to crustaceans and mollusks in either vernal wetlands or cattail marshes.
Asunto(s)
Aedes , Insecticidas , Typhaceae , Animales , Método Doble Ciego , Combinación de Medicamentos , Larva , Macrólidos , Minnesota , Control de Mosquitos , HumedalesRESUMEN
We studied the impacts of exposure to ultra-low volume (ULV) applications of resmethrin (Scourge) on monarch butterfly (Danaus plexippus) larvae and adults. In a series of 3 experiments, we measured short- and long-term survival of monarch larvae and adults, and the impacts of consuming previously exposed host plants on monarch larvae. We measured efficacy during all experiments with caged sentinel mosquitoes, and during Experiments 1 and 2 with pretreatment, treatment, and posttreatment measurements of mosquito abundance in CO2 traps. Downwind monarch larval and adult mortality were higher than upwind or control mortality up to 120 m, but not 170 m, from the spray path. In 1 experiment, monarchs exposed to spray as larvae developed into smaller adults, suggesting sublethal impacts. Milkweed host plants sprayed 1, but not 2 or 4 days previously, resulted in increased monarch larval mortality. Sentinel mosquito mortality was generally high, and CO2 traps revealed substantially lower mosquito abundance immediately after the treatment (>90% reduction) but <20% reduction 24 h after treatment. Our results suggest that ULV resmethrin applications will impact lepidopteran larvae and adults that are directly exposed to the spray but that generalizations about other nontarget taxa will require additional research. The magnitude of population-level impacts on monarchs will depend on the proportion of the population that is exposed.
Asunto(s)
Mariposas Diurnas/efectos de los fármacos , Insecticidas/toxicidad , Piretrinas/toxicidad , Animales , Conservación de los Recursos Naturales , Culicidae , Larva/efectos de los fármacos , Modelos Lineales , Control de Mosquitos , Medición de Riesgo , VientoRESUMEN
In this study, we assessed the efficacy of the American Biophysics Corporation Standard Professional (ABC-PRO) light trap, the Omni-Directional Fay-Prince trap (with and without CO2), and the Centers for Disease Control and Prevention Wilton trap as a means of evaluating populations of adult Aedes aegypti in an urban area of northeastern Peru. Efficacies of collections from each of the trap types were compared to backpack-aspirator collections and human-landing collections. Collections were conducted twice daily, 3 days per week, for 27 wk from July 2001 to July 2002. Backpack-aspirator collections yielded significantly more mosquitoes (1,764) than any of the other collecting methods with a mean of 21.80 mosquitoes collected per sampling period. This method was less specific for Ae. aegypti than were human-landing collections because only 28.3% of mosquitoes collected with backpack aspirators were Ae. aegypti. Human-landing collections yielded only 23% (554/2,411) of the total mosquitoes collected. However, more than 80% (445/554) of the mosquitoes collected by this method were Ae. aegypti. None of the trapping devices evaluated collected mosquitoes, specifically Ae. aegypti, as effectively as backpack-aspirator or human-landing collections. The ABC-PRO trap, which was the most effective device in collecting mosquitoes, particularly Ae. aegypti, collected less than 2% of the total mosquitoes (mean of 0.12 mosquitoes/sampling period), and less than 3% of total Ae. aegypti (mean of 0.11 Ae. aegypti/sampling period). We conclude that none of the trap devices evaluated in this study is an acceptable alternative to backpack-aspirator or human-landing collections for monitoring populations of adult Ae. aegypti in Peru.