An Operational Evaluation of 3 Methoprene Larvicide Formulations for Use Against Mosquitoes in Catch Basins

Abstract

Effectiveness in controlling mosquitoes in storm water catch basins in the North Shore Mosquito Abatement District (northeastern Cook County, Illinois) was determined for 3 formulations of methoprene-based larvicides (Altosid XR 150-day Briquets, Altosid 30-day Pellets, Altosid 30-day Granules) in 2017 using a pass/fail evaluation criterion, in which emergence of a single adult from pupae collected from the basin constituted a control failure. Over the course of the 16-week study, basins receiving the 150-day briquets were treated once and basins receiving the pellet and granular formulations were treated every 4 weeks, with the first treatment occurring during the last week of May. Untreated basins were also observed for comparison with the treated basins. Over the course of the study, adult mosquitoes emerged from pupae collected in 94.2% of the untreated basins that contained pupae. All of the formulations evaluated in the study demonstrated some degree of control compared with the untreated basins, with pupae successfully emerging as adults in 64.6%, 55.5%, and 21.8% of samples from 150-day briquet, 30-day tablet, and 30-day pellet–treated basins that contained pupae, respectively. Pellets reapplied every 28 days provided significantly more effective control than the other formulations. The simple pass/fail criterion for evaluating control effectiveness proved to be a useful procedure for comparing effectiveness to untreated basins and among treatments.

Standardized Operational Evaluations of Catch Basin Larvicides from Seven Mosquito Control Programs in the Midwestern United States During 2017

“…Generally, the results from the comparisons of bacterial larvicides and Altosid larvicides suggest that products formulated for a single dose of a tablet or briquet per basin surpassed retreatment thresholds more often those formulated into a dose of multiple granules and pellets. These findings agree with other field studies that have observed granular and pellet formulations to be more effective than briquet and tablet formulations (Knepper et al 1992, Nasci et al 2017, Harbison et al 2018. The reasons for the apparent differences between briquets and tablets compared to granules and pellets were not investigated as part of this study.…”

Operational Basin Larvicide Evaluations in Northern Cook County, Illinois During 2019 and 2020

“…A recent assessment of another pyriproxfenbased larvicide found longer durations (48-50 wk) in catch basins when applied at 75 to 175 g/catch basin (Mian et al 2020). Our results also support previous reports that briquet and tablet larvicide formulations may not provide longer control than 20 g doses of some granular or pellet larvicide formulations (Nasci et al 2017, Harbison et al 2018a, 2018b, Harbison 2019, and in some cases, may provide substantially less duration control. The 20 g dose of Sustain appeared to have a short duration, surpassing the failure threshold during the 1st back check (7 days posttreatment), and the 20 g dose of XR-G was 1st observed to surpass the failure threshold at 20 days posttreatment.…”

“…Since 2016, the North Shore Mosquito Abatement District (NSMAD), in north Cook County, IL, has used a standardized protocol to evaluate the district routine larvicide applications to approximately 40,000 stormwater catch basins each year , Harbison et al 2018a, 2018b, Harbison et al 2019b. Briefly, the protocol functions by scoring basins sampled posttreatment as pass or fail, based on whether there is evidence of successful mosquito production from a treated basin.…”

Do socioeconomic factors drive Aedes mosquito vectors and their arboviral diseases? A systematic review of dengue, chikungunya, yellow fever, and Zika Virus

“…A second possible explanation for the lack of a singular effect is the simple ubiquity of the vectors and the difficulty in implementing comprehensive vector control. Combating the global spread of vector populations [ 24 ] has been difficult due to high resource costs for low budget institutions [ [25] , [26] , [27] ], varying effectiveness of the chemical agents [ 28 , 29 ], concerns of their environmental toxicity [ 30 ], and the burgeoning issue of insecticide resistance [ 31 ]. Even if vector control were to be heterogeneously distributed across socioeconomic gradients [ 32 ], the large-scale efficacy of control programs is often limited.…”