The launch of VectoPrime Biological Larvicide from Sumitomo sees the problem of floodwater mosquito control being tackled using a dual active approach.
Managing floodwater mosquito populations is a key part of vector control programs in Australia. Treatments involve applying products of low environmental impact across large areas of waterways to target the larval stages of the mosquitoes.
However, there are a number of challenges in gaining successful control at a cost-effective price, not the least because the available products are better at targeting either early or late stage larval instars, but not both. The launch of VectoPrime Biological Larvicide from Sumitomo is set to overcome this efficacy issue and provide a range of benefits to those involved in floodwater mosquito control.
Floodwater mosquitoes include species from the genus Culex, Aedes, Anopheles and Ochlerotatus. The breeding areas in question are typically estuarine areas, where the water level is variable due to tides as well as rainfall. These mosquitoes lay their eggs above the water line and only hatch when the water level rises, either due to an extreme high tide or rainfall event. When these events occur, the eggs hatch in 5-7 days causing a ‘single brood’ to emerge. When these larvae emerge as adults, there is an explosion in mosquito numbers.
Single brood/floodwater mosquitoes present two complex challenges for local governments and pest control managers. First, larvae often hatch and develop at different times and rates, which complicates strategies for treatment timing and larvicide product selection. Second, floodwater habitats can be extremely unpredictable. Flooding patterns can vary greatly based on rain patterns, tidal events, irrigation timing, etc. Consequently, labour-intensive field surveillance is often necessary to identify flooded habitats and dominant life stages present (i.e., from 1st to 4th instar) before larviciding can begin.
Mosquito larviciding is generally based on short-residual biorational products using one of two active ingredients: Bacillus thuringiensis subsp. israelensis (Bti) or (S)-methoprene. These larvicides can provide cost-effective solutions for control of single-brood floodwater mosquitoes. However, each of these active ingredients delivers optimal activity against di erent mosquito larval stages. Bti performs best on 1st to 3rd stage instars, whereas (S)-methoprene performs best on the late (4th stage) instars when it prevents pupation.
As a result, multiple products are often used in a variety of scenarios, where commonly a range of instars are present. For example, while many mosquito control programs manage multiple floodwater sites, they have limited capacity to survey and treat all the sites once they are flooded.
By the time many programs can reach a site, the larvae may have already progressed to late instars, and in some cases might have a mix of early and late instars. The need for single-brood product flexibility – and the desire of programs to possess dual mode of action solutions – inspired Sumitomo Chemical to develop a next-generation tool for managing these public health problems.
VectoPrime combines Bti (strain AM65-52) with (S)-methoprene in each micro particle by utilising BioFuse technology, providing a product that delivers new levels of efficacy, flexibility and efficiency.
By combining Bti and (S)-methoprene in a single formulation, VectoPrime delivers effective control for multiple target mosquito species throughout all four instars. BioFuse technology ensures that each micro particle contains both active ingredients and they are delivered in appropriate ratios for consistent application and results.
This broad spectrum efficacy allows VectoPrime to offer the widest single brood application window – 1st to 4th instar, or even pre-flood.
This gives pest managers operational flexibility in treating a single area, but most importantly allows the successful management of multiple treatment areas over a large application window (Figure 1, above).
With its revolutionary double ‘plus’ Bti potency formulation and higher bulk density, VectoPrime can cut application rates in half for direct application to water compared to existing single brood products, delivering more value per hectare than conventional single brood options. By increasing the effectiveness of every payload, you can save on fuel, maintenance and labour costs.
