Welsh scientists working on a natural way of reducing midge activity have said their study could have implications for combating Schmallenberg disease. The scientists, from the University of Swansea, are investigating natural ways to lure and kill midges in an experiment which began as a means of controlling Bluetongue, a disease from the same family of viruses as SBV, which arrived in Europe in 2006.

The IMPACT project (Integrated Management of forest Pests Addressing Climate Trends) is examining the use of a fungus, Metarhizium anisopliae, to kill midges without affecting humans, other insect species or the environment. It is thought that midge populations will increase as climate change takes effect, thereby increasing their potential as vectors for diseases; new diseases and wider spread of known diseases currently confined to other global regions are also likely to affect Europe in the near future.

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Midges are thought to have spread both the Bluetongue and Schmallenberg viruses to Britain (in 2007 and last year respectively) when infected insects were blown over the channel from affected regions of mainland Europe. Although it is not currently known whether domestic midges are a reservoir for the schmallenberg virus, AHVLA has said this may be the case. As such, it also remains unknown whether the virus will spread further this year when midges become active.

The researchers had suggested that the fungus, which is already known to kill midge larvae, could reduce both midge populations and inputs of harmful pesticides. Further work revealed the V275 strain of Metarhizium anisopliae fungus has potential for use in control programmes, with some applications having a 100 per cent success rate for killing adult midges within five days.

Professor Tariq Butt, of Swansea University, said of the innovative new approach, “Current control measures rely on synthetic pesticides, which pose a risk to humans and the environment, whereas natural alternatives do not, and with climate change projecting warmer, wetter weather these could prove a very useful alternative in reducing midge populations.

“However, the agent needs to be tested in different field conditions to show it is robust, efficacious and does not pose a risk to non-target invertebrates.”

The team will now conduct field trials of their fungus. As well as investigating the potential to spray midges with the fungus, teams in Swansea and Aberystwyth are developing lures, using chemicals from human and animal odours to attract midges to ‘kill sites.’

The lures could be placed around breeding sites, such as manure, trees and ponds, to kill off midges before they have the chance to spread disease within or between groups of animals. However, the fungus, which occurs naturally in soil, must undergo rigorous trials as it is known to affect over 200 insect species and the scientists on the IMPACT project do not want their discovery to have unintended consequences.

As well as having implications for diseases such as SBV and Bluetongue, the IMPACT scientists believe their findings could be useful to combat diseases spread by insects elsewhere in the world, including regions affected by malaria. Britain was declared free of Bluetongue last year; the disease has also been brought under control in mainland Europe, though restrictions still stand in countries where infection persists including France, Spain and Italy.

Professor Butt said that, if found to be safe and effective, the new lures could be on the market in the next few years.

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