Corn earworm pressure often increases as we head into September. With turbulent weather patterns originating in the Gulf of Mexico, flights of airborne moths are generally quite high. As the tradewinds mix with the cooler air of the great lakes, these high populations are dropped into Southern Ontario. Any sweet corn at the green silk stage is highly susceptible to corn earworm infestation.
For earworm control, cover green silks with an insecticide such as Coragen or Voliam Express. Avoid insecticides from the pyrethroid family. Corn earworm are known to be resistant to the pyrethroids. Lannate TNG is a good rotational partner for Coragen and Voliam Express.