Author Archives: Trent Elwing

Codling Moth 1st generation 2021 have begun flying in King County

Lifetime and longtime STFS member Marilyn T. reported this past Friday (5/21/21) a total of 10 adult codling moths caught already during 2021 in a trap located near the Seward Park area of South Seattle. Reminder: adult codling moths lay eggs on or around pome fruit trees; larvae emerging from these eggs chew into developing fruit leaving behind a dark brown excrement-filled path and core. Yuck.

Always thorough and thoughtful towards amateurs, Marilyn took the time to type out that several nearby (Woodinville and Puyallup) WSU AgWeatherNet weather stations had recorded by last Friday “growing degree day (°F) accumulation base temp 50 °F” or “DD base 50” data of slightly less than 175.

175 is the DD base 50 threshold for first emergence of codling moth and was established from WSU research published in Orchard Pest Management. Marilyn mentions that this threshold is based on observations made in central WA, but also appears to be an accurate predictor in western WA.

In short, Marilyn has observed adult codling moth flying already in Seattle, and nearby WSU weather data coupled with pest management protocols predict codling moth first generation emergence as of now in and around King County. So…

Whatever your strategy to protect your pome fruitlets from codling moth, you should implement it now right after thinning fruitlets to one and only one per cluster.

Click on link Pome Thinning and Barrier Protection for pages from recent STFS newsletter covering pome thinning, codling moth, apple maggot and barrier protection options.

Click on link Extreme Maggot Barriers for ordering information on these nylon footies sold by STFS. STFS will have Extreme Maggot Barriers for sale with no shipping costs on Saturday June 5th 10 AM to noon at STFS demonstration orchard in NE Seattle’s Magnuson Park.

Barrier netting is also available to STFS members but must be pre-ordered. See Pome Thinning … link above for details.