Temephos or Abate insecticide emulsifiable concentrate formulation applied at the rate of 10% with a salt water carrier and discharged through a telescopic boom from apparatus fitted to a small boat has been 98% effective against Culicoides molestus larvae in canal banks. Equipment described enables the application of Abate E. C. at 0.78 Kg. per ha., and 20 Km. per day are readily achieved in all weathers.