Winterkill recovery
We have reports from growers that many areas that experienced dramatic winterkill are now looking much better than predicted based on the conditions of the vines in the spring. One of our bogs had extensive death of uprights (and terminal bud death/injury even on uprights that made it through the winter) and has still somehow still managed to set fruit. The fruit there is small, and other growers have also shared the fruit on winter-injured beds is looking small despite a decent amount of vegetative growth above the fruit.
Insects
This has been a delightfully quiet insect week! A few cranberry fruitworm berries can be found. Remember that a spray targeting larvae in the berry is generally unsuccessful. The larvae are protected behind their silk doors inside the fruit. Moth flight is down this week (based solely on State Bog). Historically, some bogs see a second moth flight at the end of July with egg laying just at the start of August so if you are thinking “1 more fruitworm spray”, you may want to drag your feet until next week or better yet 2 weeks!
Weevil numbers should be dropping as the adults leave the bog to overwinter in the woods. Unless you detect very high numbers (30+), it is not reasonable to treat for them. Flea beetle may start showing up as we move into August, and again, unless very high numbers are found or significant damage is seen, the cost (and trauma) of a Diazinon spray, the only management option, may not be justified. They generally feed on the overgrowth areas, but very high numbers could damage next year’s developing bud.
Disease
Red fruit with scaring caused by the viruses Tobacco Streak Virus and Blueberry Shock Virus are now very visible on infected uprights. There is no management strategy for these viruses. Infected plants do not necessarily show symptoms every year. In the years after the initial infection, uprights can produce healthy-looking berries, but the vines may continue to test positive for the virus. It is typically thought that these viruses do not impact overall yield since symptoms are patchy and transient - however, we have been hearing from some growers that they do think there are yield impacts for some of the newer “super hybrid” varieties. If you think that your farm is experiencing losses from these viruses, please let us know!
Remember that fungicides applications to manage fruit rot pathogens are effective when flowers (and to some extent pinheads) 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
Fireweed is now a few inches above the cranberry canopy, and it is too late to manage it with Callisto.
We have seen thick and heavy dodder on some farms, but other areas with historic dodder problems seem to have almost none this year! Some growers with dense patches have been raking off the mats to allow light and air to better reach the cranberry canopy. This can improve the cranberry plant health, but raking does not remove the embedded dodder, and where the dodder flowers are present there will still be some seed production.
Lots of growers are spraying grass with Intensity One/Select Max, and poverty grass does not seem to be flowering yet (in places I have observed) so the window to get out a first or second applications is still open (minimum 14-day interval between apps).
Lots of growers are also applying QuinStar. Although registered for many years, use in MA has been almost non-existent until recently. We are still learning what this herbicide controls and how it works in the field. I am interested in hearing about your experience. In general, it has proven very safe on cranberry. But occasionally we do see symptoms on vines (small or misshapen leaves, long spindly runners/rights with unusual leaf spacing). I have yet to document or hear about yield impacts associated with those symptoms, and they are patchy and not widespread throughout whole beds.