Tobacco Streak Virus (TSV) and/or Blueberry Shock (BlShV) infected berries are showing up on a number of bogs, and symptoms are red/brown scarring on fruit. Do not be fooled into thinking this is fruitworm damage (fruitworm berries also turn prematurely red but have frass and a worm inside!). TSV and BlShV can be found on many (if not all) varieties like CQ, MQ, ST, and H but certain cultivars like BG seem especially prone to showing symptoms. There is no treatment for these viruses, and at this point no prevention practices. These two viruses are visually indistinguishable and can only be differentiated by diagnostic testing.
TSV was first noted in WI in 2012 but has since been found all over the cranberry growing regions. Infected plants do not necessarily show symptoms every year. In many cases after the first a year vine shows symptoms, those uprights will go on to produce healthy-looking berries in the following years - but the vines will continue to test positive for the virus. As it creeps slowly and spottily across beds, it can cause some localized damage but is not thought to impact the overall yield of the bed. There are some reports from growers it does actually impact yield on BGs. It is unknown if stress can cause a reoccurrence of symptoms in years following the initial infection.
We are assessing crop loss and monitoring populations in the newer varieties, so if you see lots of damage please reach out and let us know!
Here are some links to fact sheets with pictures and more info:
Insects.
Now that rented honeybee hives have been removed from most bogs, Actara applications for weevil could be applied. Be aware that much of the damage to pinheads has already occurred, and weevil numbers should be going down naturally as they move off the bog. You would have to have a very high weevil count (30-50/sweep set) to actually make a spray at this point in time worthwhile.
The recommended way to management cranberry fruitworm is 2 Altacor applications, at the high rate, spread 10 days apart and these have already been applied by now. If additional applications are needed or warranted, Intrepid/Invertid or Delegate are the only choices – checking for eggs or monitoring moth flight are 2 ways to get some information on CFW pressure on your bed. Moths are still flying at State Bog, and both Ocean Spray and CGS are finding a few eggs in collected berries.
Black bug adults have been found on a few bogs with associated spring damage. If you have a poor set, it could be the culprit. Casebearer are also being reported, albeit at low numbers, but on a fair number of bogs.
Disease.
Remember that fungicides applications to manage fruit rot pathogens 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.
INDAR beware! If you are trying to get one more fungicide on, be aware that Ocean Spray Export has a restriction on Indar with a 90-day PHI!!
Weeds.
Poverty grass is at an active growth stage now, and the active growth period is the best time to apply a grass herbicides for maximum efficacy. That window won’t last long - poverty grass can develop quickly, and herbicide treatments will be much less effective after it flowers (when you can see the tall stalks shooting up)!
Fireweed plants are now too big to be controlled with Callisto, so chances are if you have it on your bog now it will go on to flower and make seeds for next year. Consider a preemergence herbicide next spring, or an early Callisto application next summer.
Lots of growers are applying QuinStar now. Keep in mind that QuinStar has a relatively long 60-day PHI and needs at least 30 days between applications.