With so much stagnant water lying around and the possibility of warmer weather on the way, experts say many areas could be about to be invaded by swarms of the blood-sucking insects.
Only a cold snap can stop the insects now, said biologist Norbert Becker from the German Mosquito Control Association (Kabs).
“If it stays very cold, then [the mosiquitoes] don't want to bite or fly,“ said Becker, but if it gets warmer, “then you can safely say that they will make themselves very apparent.“ In many places numbers could reach plague levels within the next few weeks, he added.
Those living along the Elbe, Oder, Donau, Rhine and other rivers should prepare for an inundation of mosquitoes, after flooding could trigger numerous eggs laid in damp flood planes to hatch.
“We can assume that everywhere where there has been severe flooding and there are flood planes there, or also flooded fields, that a plague of mosquitoes is on its way,“ said Becker.
Before females can lay eggs they must mate with a male and consume some blood. Then it is only a matter of time before the insects arrive, depending on the weather.
“The development of the larvae in water depends on the temperatures,“ said Becker. If it gets warmer, this can take one week, but up to two or more weeks in cold weather.
Becker's Kabs organisation has recently been fighting mosquitoes along the upper Rhine by spraying breeding grounds with a protein mixture which destroys the insects' gut and kills them.
But no such precautions have yet been taken along the Elbe, said Becker, due to a lack of staff with experience of the rare extreme flooding conditions.
“They have to know the breeding grounds, they have to map them, they have to have the infrastructue – people who know what to do,“ said Becker.