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Cranberry IPM Message

Some early grasses are up.  Growers are spraying Poast and/or Select for control of these early emerging grasses.  These herbicides work best when applied before grasses flower.  Be sure they are tall enough to have enough leaf area to absorb the herbicide (usually 4-8" tall is a good guide).  Grass herbicides CANNOT be applied through the chemigation system.  They will only control TRUE...

Dodder seedlings (~1/2” long) were reported on April 25, occurring in a bog in Rochester. Applications of Casoron for dodder control will be going out soon.  Be sure to check your own bog for early emerging seedlings.  We have demonstrated improved efficacy with higher rates and/or two applications of Casoron (on a bog where control was inadequate).

Now is the time to be looking (and spraying) for winter moth larvae out on the bog!  Advanced bogs, hybrid cultivars, and sanded bogs will be warmer and more likely to have growth that is appealing to WM now.  These bogs will likely need to be sprayed this week.  Later varieties and colder areas will likely need applications next week.

The weather has been and will continue to be very hot.  This can be stressful for the vines.  Monitor as needed to make sure the vines and fruit are not lacking for water.

If you have flea beetles out there and have numbers "too high" to count, you should spray Diazinon as soon as possible. Cranberry weevils (second generation) are out and abundant in some cases. The threshold for spraying is higher for the summer generation; an average of 9 is used to trigger a spray. Remember Actara is Zone II regulated and highly toxic to bees.

Early rot has already been reported on Early Blacks and Stevens. This fruit rot disease is one of the first to be observed during the growing season. Infected fruit have brown-dark brown spots with concentric rings and as infection progresses, black, pimple-like structure (pycnidia) may be visible on the fruit surface.

We have gotten a few calls about gypsy moth. There is no recommendation to treat for the moths that folks are reporting (both brown moths and white moths); IPM recommendations target larval stages. To the best of our knowledge, gypsy moth has only one generation per year, contrary to some information going around in the rumor mill. You may see dead caterpillars on tree trunks.

Altacor and Delegate are still your best choices for cranberry fruitworm control with respect to residual and bee safety compared to Diazinon, so we recommend using those products over Diazinon.  If you are concerned about sprays going out in unstable weather pattern, Altacor should have good residual and rainfastness.  Please use the traditional cranberry fruitworm timing for Howes, spraying...

Please let the Entomology lab know if you have a scale problem or if you think you have a problem. They can help you diagnose it and they want to know how much is out there. Timing for good control is critical so do not wait too long or try to time with other sprays; just go out and get it done.

Please let the Entomology lab know if you have a scale problem or if you think you have a problem. They can help you diagnose it and they want to know how much is out there in the industry. If you have scale, it is time to spray. As far as fruit rot, it is also time to be putting out first fungicide.