The Cranberry Station is hosting another Bogside Meeting July 14th 9-10:20. You can join the meeting by Zoom or in-person in the AD Makepeace Room at the UMass Cranberry Station (no registration required, and no credits offered).
Please contact Giverson Mupambi gmupambi[at]umass[dot]edu (gmupambi[at]umass[dot]edu) for the Zoom link.
Insects
Cranberry weevil has been reported by several large growers at very high counts (50+). For most growers, Actara is the only option at this point in the season, but it has extremely high bee toxicity. If you produce domestic fruit, Fanfare is an option if have not used your second spray yet. Note that most handlers’ restriction it with either 30- or 60-day PHI. You must wait until your bees are pulled off your property or be quite sure there is no bloom on your bog in order to spray Actara (or Fanfare). In addition, be aware your native bumblebees may still be present on the bog and can be severely impacted by a weevil spray. Weevil damage on pinheads with drill holes and aborted fruit is already apparent. Be sure it is worth it to spray, as weevil will likely move off the bog in another week or two. If you have 10 or 20 counts when you sweep, it may not be worth it. If you have 40 or 60, it may well be.
Two Altacors, at the high rate, spread 10 days apart is the best recommendation for cranberry fruitworm. If an additional application is needed or warranted, Intrepid/Invertid is the next compound of choice if you have fruitworm or sparganothis pressure. Delegate is another option, but it is very expensive and best used towards the end of the month. At all sites monitored with pheromone traps, the flight of both black-headed fireworm and Sparganothis fruitworm was extremely low or non-existent. The running theory is that Fanfare had a huge impact on populations.
Adult black bug and adult blunt-nosed leafhopper have been found at isolated sites, as well as a few reports of casebearer.
Disease
Bloom moved quickly! Most growers have applied their 4th fruit rot fungicide spray by now. Remember that fungicides are effective when flowers are present, and once the fruit has set and begun to increase in size (mid-late July), fungicides are no longer necessary or effective.
Weeds
As the cranberry bloom period comes to an end, growers are thinking about postemergence herbicides. These include popular compounds like clethodim (Select Max/Intensity One, etc.), mesotrione (Callisto/Explorer, etc.) and this year again quinclorac (QuinStar).
Poverty grass is at an active growth stage, so this is the best time to apply a grass herbicide for maximum efficacy. If you can treat it at least twice, you will get better control. Repeat applications need to be at least 14 days apart and there is a 30-day PHI for clethodim products (and an even longer 60-day PHI for Poast which contains sethoxydim).
Remember to ALWAYS include a surfactant with your grass herbicide – it is needed for these types of herbicides to work. Use 1-4 pt/A of NIS or LI 700 for chemigation applications. If you are using another method to spray (like a drone) that uses less water, the amount of adjuvant will be a percentage of the final spray volume, and this info can be found on the pesticide label.
You can apply up to two applications of mesotrione (Callisto) per year. If you have not already made an application and want to squeeze in two postemergence apps, remember that apps need to be at least 14 days apart and there is a 45-day PHI.
Dodder seems to be suddenly exploding on some (but not all) the bogs. I have talked to some growers that usually have dodder and are having a hard time finding it this year. Hard to know if it due to climate, or that management practices from previous years have taken a toll on the seed bank and the pressure is just lower now on those beds.
Control measures work best before dodder flowers (which it is starting to do in spots). A postemergence application of Callisto by chemigation for dodder seems to work very well for some growers and not at all for others! We are not sure if it is timing issue, surfactants, variation in the dodder itself, or another unknown factor that leads to such mixed results from bog to bog and grower to grower. Reports from other areas are that QuinStar works best for dodder when an early season application (soon after dodder germinates and begins seeking host plants) is followed by an application in July after cranberry bloom. A single post-bloom application did not seem to be effective for dodder control in the year of treatment BUT some growers feel they get control the year after they apply QuinStar.
If your dodder is in isolated patches, you can do a spot treatment spray with concentrated Callisto. This has been demonstrated to be effective. We have the SLN label on our web site under Services/Pesticide Labels. Remember that spraying before dodder flowers is much more effective than spraying after flowers or seed are present.