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IPM Message for Cranberry Growers: May 1, 2020

May 1, 2020

Not much has changed since last week.  The weather has been either cold or wet or both.  Bud development has been slow to progress.  The below is similar to what I reported last week, just briefer.

Most handlers are permitting spring applications of Bravo or other chlorothalonil products for upright dieback control; check with your handler before using.  Applications typically go out between April 25-May 15.  Best results occur when the fungicide is applied when the bud is expanding and starting to elongate. 

If you think you have Phytophthora, make sure you get a diagnosis first before applying any fungicides.  Please contact Leela at 334.728.1025 to arrange a drop-off. If you are in a position to apply fungicides, the first application goes out between April 25 and May 15. 

First applications for Fairy Ring go out in early May at budbreak. A combination of Indar and Abound are the recommended fungicides and they are applied as a soil drench. You should treat the affected area plus a 10 ft outer margin. To stay within the label rate per acre, you can treat about 4300 sq ft.

We will be holding a virtual (zoom) Grower Lunchtime Bogside on Wednesday May 6, 2020 12:00-1:00 PM. One contact hour will be offered. Please contact Robyn Hardy at or 508-295-2212 x10 for the meeting information.

Within another week or so, the window will be closed to use Zeus, our new herbicide. It should go out between spring dormant and cabbagehead. Please see our March 2020 newsletter for more information.

Also within the next week, if it warms, it would be time to start scouting for dodder seedlings. Apply Kerb when you start to see emerging seedlings; with Casoron, you should wait about 7-10 days after first emergence.   If you think you missed FIRST emergence, apply either herbicide at your next available window.   We have seen improved control with Casoron with 2 40-lb applications separated by about 3 weeks. Remember Kerb is restricted or prohibited by most handlers, so check with yours before applying.