This is the first cranberry IPM message for the 2026 growing season. Regular IPM messages will be sent out weekly on Fridays. You can receive the IPM messages by email, by checking our website, or by calling 617-928-4000 to listen to our recorded message.
These messages will contain information about what we are currently seeing in the field, or what we expect to see in the near future. For detailed information on management recommendations (rates, timings, specifics for your farm or situation), call the Cranberry Station (508-295-2212) and talk to an Extension Specialist and look in the Chart Book.
Insects. The cool weather has kept bugs in check so far. Only one sad weevil and one sad green spanworm (or winter moth) have been reported. With temps in the 60’s, we expect more to bugs on the bog to develop soon. Cranberry buds are progressing and will provide the food source that both weevil and spanworm are waiting for. Weevil can be found on blooming blueberry around the bog, so they are ready. Black bug and leafhopper may have hatched but are extremely small at this point and not readily visible. The non-pest collembola are getting picked up in sweep nets, but not much else!
Weeds. Despite the cool weather keeping the bugs in check, we have been seeing many weeds developing earlier than usual.
Dodder is starting to emerge in warm spots – so make sure to scout your bogs to time your herbicide applications! If you had dodder last year, you will certainly need to plan for managing it this year. It is a prolific seeder, and the seeds can survive in the soil seed bank for years. Consider preemergence herbicides like Kerb, Casoron, and QuinStar (used pre or post).
Growers are seeing some species of grasses actively growing and doing early applications of grass herbicides (like Intensity One and Poast). Always be sure to include an adjuvant with these herbicides!
Red sorrel is already flowering in some spots!
Pine trees saplings are showing up on many beds. Easy to pull when small before their roots are well developed and can be wiped with glyphosate even now.
Haircap moss is already starting to reproduce (via spore production).
Call Katie Ghantous for management recommendations (508-970-7634).
Diseases. Orangey brown to bronze discoloration and heavy defoliation of uprights scattered throughout greening vines may indicate Upright Dieback (caused primarily by Phomopsis vaccinii). Emerging buds are particularly susceptible to infection during and shortly after bud break. Treatment for Upright Dieback using chlorothalonil or copper products can be made from bud break through bud expansion, targeting the period with the newest growth but before roughneck stage. This window is expected to occur within the next one to two weeks for many cultivars. For growers producing export fruit, many handlers have restricted chlorothalonil use after bud elongation or with a 120-day PHI.
Overall stress management is also important for reducing disease severity. Fungicide applications targeted for fruit rot management may also provide some protection against Upright Dieback during early and mid-season infection periods.
If you suspect Upright Dieback or Phytophthora Root Rot in your bog, or have any disease-related questions, please contact Leela Uppala at 508-970-7644 or suppala[at]umass[dot]edu (suppala[at]umass[dot]edu).
Other topics to consider. For those of you holding late water (LW), 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 fully drain before applying. You still need to scout your LW bogs for spring insects, even though you will likely be able to omit the early insecticides. Nitrogen needs for the vines are lower on LW bogs, so you can usually skip your first N application and/or reduce 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 needed before bloom but go out and look.