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IPM Message for Cranberry Growers: May 10, 2019

May 10, 2019


Kerb Use Approved for Dodder Control as Emergency Exemption for 2019 in MA

All applicable directions for use, restrictions, and precautions on the full EPA label, including WPS, must be followed.  A maximum of 2 PRE-emergence applications per acre can be made per season.  One application can be made at the rate of 2.5-5 pt/A, not to exceed 5 pt/A.  Alternatively, two applications can be made at 2.5 pt/A, not to exceed a total of 5 pt/A.  Although the herbicide should be watered in, do not apply just prior to a major rain or lengthy frost protection event.

Handler restrictions will likely apply.  Contact your handler PRIOR to using Kerb!!

You must have dodder on your bog to use Kerb under this Specific Exemption.  Scout NOW to find seedlings and apply once seedlings are found.  Search in the canopy and/or in areas where you off-load your fruit and trash.  These are the best places to find dodder seedlings.  Follow your application with 0.1-0.2 inches of irrigation or rainfall.  You must wait at least 20 days between applications.  A 75-day pre-harvest interval must be observed. The REI is 24 hr.  The exemption expires June 30, 2019.  MDAR requires that all applications are reported to them by November 30, 2019.  Labels and MDAR reporting forms will be available at all ag retailers, at the Cranberry Station, and on the Cranberry Station web site.

Kerb is Zone II-restricted. If you are in a Zone II, please call Hilary at the Station to determine if you qualify for a letter.  You cannot apply Kerb in a Zone II without a qualifying letter. Drop the water level in your ditches prior to application. Keep the planks in the flumes and plug all leaks prior to applications. If you can hold water on the bog after the application, please hold for 24-72 hours. Avoid all off-target application by using half-heads or screens as needed.

Late Water Bogs.  For those of you holding water on inland bogs, the water should come off by May 15. Coastal Plymouth County bogs should have the flood removed around May 20 and Cape bogs should pull water in late May.  Remember that the frost tolerance will be 29.5 F as soon as the flood is removed, no matter what the buds look like.  Casoron can be applied for dodder control after the flood is removed, but wait for the bog to drain before applying.  You still need to scout your LW bogs for early spring insects, even though you will likely be able to omit the early insecticides.  Cutworms and spanworms can still be found on LW bogs.  Cranberry weevil is NOT impacted by LW and may need management depending on what numbers you pick up.  Nitrogen needs for the vines are usually less on LW bogs, so you can usually skip your first N application and/or reducing the fruit set dose.  It is best to wait at least 2 weeks after flood removal and add small amounts and monitor the progress of growth.  Generally, no fertilizer is need before bloom, but go out and look.