As the onion harvest continues across the US Northwest, Washington State University is reminding growers to keep their eye to the field and to the sky. According to WSU’s Tim Waters, when it comes to over winter onions, it’s important to watch out for leafminers. Although the American Serpentine leafminer is a fairly sporadic pest across the Columbia Basin, several fields were infested with the pest in 2016, meaning it could return again.
“We have the American Serpentine leafminer that can cause problems on over winter onions. So we recommend growers put yellow sticky cards, sticky traps out for those, and look for those and when they see a high number of those treat for that pest.”
Dr. Waters added it’s also important for growers to watch out for rain showers this time of year. He noted when the tops of the onions get wet, the out scales retain moisture. “So, it’s really important for growers when they can to wait to harvest those till the tops dry out well or make sure they get a lot of air movement in storage in order to keep those bacterial and fungal pathogens from exploding in storage.”