Identification of Larvicide-Resistant Catch Basins from Three Years of Larvicide Trials in a Suburb of Chicago, IL

Abstract

The tens of thousands of catch basins found in many urban areas are a primary target of local vector control agencies for seasonal application of extended-release larvicides. A concern with using larvicides in these structures is that active ingredients can be hampered by high flows, debris, and sediment, all of which are common to these structures. As such a certain proportion of basins may be “resistant” to larvicide treatments due to site specific characteristics that may promote these and other factors that hinder larvicide action and/or promote mosquito infestation. Analyses from three years of larvicide efficacy trials suggest that over a quarter of basins in the study area may not be receiving adequate protection from a single dose of larvicide that is routinely applied. Implications of increasing the dose and/or toxicity of larvicide treatments are discussed further.

New adhesive traps to monitor urban mosquitoes with a case study to assess the efficacy of insecticide control strategies in temperate areas

“…MET has the advantage to directly assess the presence of emerging adults (as opposed to larvae or pupae) without the need of high numbers of larval dips inside the catch basins (which are needed to collect a representative number of larvae/pupae [ 47 ]), thus also eliminating the need of rearing larvae to the adult stage, when species with similar larval morphology are present [ 48 ]. Moreover, MET can be exploited to assess the lethal effect of larvicide-treatments in catch basins, which represent a fundamental component in the control of the abundance of urban mosquitoes [ 49 ] and are very commonly carried out in infested municipalities in Italy [ 21 ]. Results obtained showed that, although all monitored catch basins were shown to be visited by Ae.…”

Environmental stochasticity and intraspecific competition influence the population dynamics of Culex quinquefasciatus (Diptera: Culicidae)

“…Insecticide-based larvicides (e.g. those that directly lead to larval mortality, such as Bacillus thuringiensis , bti) that present low efficacy on larval mortality in a catch basin [ 9 , 11 , 48 ] could be relieving the population from strong competitive pressure, leading to an initial reduction in productivity but a rapid bounce-back of populations after rain events flush or dilute chemicals in catch basins. Conversely, insect growth regulators (e.g.…”

“…Such a relationship is supported through our investigation of Model A* sensitivity to adult and larval perturbation. The interaction between competition release and insecticide regime efficacy, though little studied, can have high value in informing vector control strategies relying on larval control [ 1 , 9 , 11 , 48 , 52 ].…”

“…larval dynamics and response to rainfall [ 39 ], are known to maintain high abundance of Cx. quinquefasciatus [ 37 , 46 ], are widely distributed in urban areas of the USA, and are the most commonly targeted structure in urban larval control campaigns [ 9 , 11 , 47 , 48 ]. The model also assumes that the effects of evaporation within the system are negligible, and that oviposition site selection of Cx.…”

“…In addition to application cost, vector management in the Cx. quinquefasciatus system is limited by immature larval habitat characteristics [ 9 , 11 – 13 ], fine scale heterogeneity in virus transmission [ 7 , 14 ], and high levels of uncertainty in the prediction of disease outbreaks.…”