Insects.
Altacor, Altacor, Altacor! Timing for your cranberry fruitworm spray is NOW! Be aware that the new formulation, Altacor eVo, is more concentrated and used rate lower than the older formulation of Altacor (2.2 oz vs 4.5 oz per acre). Two Altacor sprays (back-to-back, min. 7-day interval between applications) are recommended. If you feel you have heavy cranberry fruitworm or sparganothis fruitworm pressure, additional sprays could be Intrepid followed by Delegate at the end of the month.
The summer generation of cranberry weevil is active now, particularly on the super hybrids. Be aware that the only option for management is Actara which is extremely toxic to bees and should NOT be applied if bees are still working the bloom. Fanfare may be an option if you are a domestic grower and your handler allows a second application, but Fanfare is also extremely toxic to bees.
Adult black bugs have been picked up at a number of sites, so be on the lookout if you do sweep your bog. They are small (<¼") and move fast.
Disease.
Many growers have already applied their third fruit rot fungicide. Due to the “Extremely Poor” Keeping Quality Forecast, a fourth fungicide application is advised.
While the recent focus of pathology management has been towards fruit rot, keep in mind that if you have a bog or a section of the bog diagnosed with phytophthora root rot that summer can be an ideal time to treat for phytophthora (after improving your drainage). You can apply phosphonates or soil phenylamides when soil temperatures are conducive for root development and pathogen multiplication (June, July and August).
Weeds.
Poverty grass is at an active growth stage in many locations, and active growth periods are the best time to apply a grass herbicide for maximum efficacy. If you can treat it at least twice, you will get better control. If you are choosing to wait until after bloom to apply herbicides, prepare to treat poverty grass as soon as you can before it begins to flower.
Fertilizer.
Many growers applied their early-set fertilizer (made at 75% bloom) last week and are thinking about their late-set fertilizer (to be made at 75% out-of-bloom). The late-set application should deliver the remainder of your bed’s seasonal nitrogen needs. For example, if you planned to deliver 40 lb/A N for the year and you applied 8 lb/A at roughneck (20% of needed), another 24 lb/A N at early-set (another 60% of total needed), you will need to apply another 8 lb/A (20% of total needed) to reach your 40 lb/A N goal.
Some growers have been taking a different approach for the newer “super hybrids”. This tactic divides up the “set” fertilizers into smaller and more frequent doses. Starting with the first application at early set, and then following that with 2 more applications on a 7-day schedule.
Please reach out to Peter Jeranyama peterj@umass.edu if you have any questions regarding fertilizer rates and applications.
