Pest managers know that to control a pest, they have to get to the root of the problem. With mosquitoes, that means treating the larvae as well as the adults.
When thinking about insect control, it’s understandable that the initial focus is on killing the life stage that causes the problem, which in most cases is the adult. However, in taking an integrated pest management (IPM) approach, there are different and smarter ways to design treatment programs that provide a more complete and longer-lasting result. This is certainly the case when trying to control mosquito populations.
Mosquito treatments often focus on targeting the adult mosquito either through fogging or through treating mosquito hiding places to create an ‘interception zone’. Although both techniques are quite successful in delivering a significant drop in mosquito populations, they don’t deal with the root cause – mosquito breeding sites (such as those pictured above). Without taking care of the source of the problem the mosquito population will rebound.
In Australia, the primary strategy for reducing mosquito populations in vector control programs is treating waterways. The use of products containing Bt (Bacillus thuringiensis) and IGRs (insect growth regulators) to target the larval stages is a highly effective strategy to suppress mosquito populations. Pest managers have access to a similar product for use in residential and commercial accounts with Sumilarv Granular.
Sumilarv Granular contains the IGR pyriproxyfen, which is a juvenile hormone analogue. Pyriproxyfen has a unique mode of action that not only kills the larval stages, but reduces egg hatch and prevents the emergence of adults from the pupal stage at very low doses.
Finding and treating breeding sites is a targeted approach to mosquito control and once located, control can be confirmed as the mosquito larvae are fixed in one location – they aren’t free to fly around and hide like the adults. Sumilarv Granular comes in pre-dosed sachets, so adding Sumilarv to breeding sites is quick and simple with the slow release formulation providing protection for several months.
The environmental and toxicological profiles of Sumilarv are very favourable. In accounts where broadcast spraying of insecticide may be undesirable, both the application method and mode of action of Sumilarv means non-target insects are unaffected. The mammalian toxicological profile is so benign that the sachets can be used in drinking water sources.
However, it should not be applied to open course waterways as it can impact crustaceans.
Pest managers may think it is a challenge to locate all potential mosquito breeding sites on a property, but with Sumilarv active at extremely low levels and the phenomena of auto dissemination, they don’t have to! Pyriproxyfen has an LC50 rate as low as 0.012 parts per billion on Aedes aegypti (Sichuincha et al., 2005). When adult mosquitoes visit a treated breeding site they pick up small doses of Sumilarv and transfer pyriproxyfen to untreated breeding sites.
Although resistance to pyrethroids is unlikely in most residential and commercial accounts in Australia, if an account is receiving regular mosquito treatments the inclusion of Sumilarv as part of the program will help minimise the development of resistance.
The use of Sumilarv should be key tool for pest managers in mosquito control, ideally as part of an integrated approach, but in situations where insecticides cannot be sprayed, it may indeed be the only option.
Reference: Sichuincha et al. (2005). Potential use of pyriproxyfen for control of Aedes aegypti (Diptera: Culicidae) in Iquitos, Peru. J. Med. Entomol. 42 (4): 620-630.