Our 2024 Spring Mini Clinic saw record-breaking attendance. The live location at Whittlesey Cranberry Co in Cranmoor had 52. Livestream locations were held in Tomah (Valley Corp, 20 attendees), in Manitowish Waters (Bartlings’ Manitowish Cranberry Company, 11 attendees), and newly this year in Minong (Jack Link’s Aquatic Center, 17 attendees). With an action-packed agenda, we still found 5 minutes to step outside to view a bit of solar eclipse through the clouds.

Following is a high level recap for each of the presentations. For further questions, contact the presenter or Allison (allison.jonjak@wisc.edu) .

Cranberry Weed Management Pre Season Update, Jed Colquhoun

Devrinol must be applied after planting, before weeds emerge. It has no effect on emerged weeds. All Devrinol applications must be watered in within 24 hours of application in order to reduce photodegradation, and to get the product into the weed germination zone. Application rates for new plantings are much lower than those for established vines.

Evital must be applied to dormant vines, before weed growth resumes. Flooding after application results in poor weed control as well as injury risk due to puddling. Irrigation after application does improve weed control, just avoid puddles.

The Endangered Species Act Vulnerable Species Pilot Project will be rolled out on August 30 of 2024. Be prepared to use Bulletins Live Two, the EPA’s interactive website tool, to comply with new mitigation measures. A demo of Bulletins Live Two will be given at the May Brown Bag.

Grower Polls, Allison Jonjak

Cold Hardiness Prediction Model, Amaya Atucha

The prior method of cold hardiness evaluation was visual assessment of uprights. Because this was labor intensive and subjective, the Atucha lab has developed a new, quantitative method of evaluating cold damage via electrolyte leakage. This method produces more reproducible results and will result in speedier updates to the Cold Hardiness Prediction Model in the future.

Altacor Update, Bell Verbeten, FMC

Along with an update on various insect protection modes of action, Bill reminds growers that when you receive the new product formulation Altacor eVo, to note that the concentration has changed. While Altacor original was 35% active ingredient, the new Altacor eVo is 70% active ingredient. This means that the old formulation was applied at 4.5 oz/ac. The new formulation needs to be applied at 2.2oz/ac. As always, the product label is the law, and you should always check with your handler before making changes to your chemistry practices.

Dewpoint Frost Considerations, Amaya Atucha and Allison Jonjak

Please see the accompanying article in CCMJ 37.1.

Cranberry Viruses, Leslie Holland

While infected uprights can recover (or stop showing symptoms) of Tobacco streak virus and Blueberry shock virus, they may still carry virus-infected pollen. Additionally, some viruses have a latent period, where infection occurs but symptoms take several months or even a year to develop. Beds where a virus has been identified should not be used as a source of cuttings for new beds.

The best time to scout for viruses is during early fruit set in mid to late July. Berries turn red prematurely, so look for hot spots of infected uprights. Especially scout for scarring during this period, because as healthy fruit turns red, the infected regions will be more difficult to find by contrast.

The Holland lab is actively pursuing virus research, and would love to collect virus samples. If you have either Blueberry shock virus or Tobacco streak virus, please contact laholland@wisc.edu to set up a confidential method for research participation.

SpargDD Harmonization Task Force Update, Allison Jonjak

The project to establish SpargDD (that is, growing degree days specifically for timing the phenological stages of sparganothis fruitworm) is under way. UW faculty, growers in central and northern WI, ag scientists from handlers, as well as engineers with temperature sensor systems are all participating. The goal of the project is to ensure all future research at UW takes place using the same constants, and to streamline the use of models so that growers can get an easy-to-use application window alert. The ultimate goal is to achieve equal or better application efficiency, using equal or fewer sprays.

While taking this project to its final conclusion plug-and-play conclusion will require more time and involve engineering, growers who are interested in implementing the model in its current form can get involved by contacting allison.jonjak@wisc.edu , or by using the below parameters at app.blossom.ag/gdd . (Thank you to John Moss and Blossom.ag for sharing this free tool with all growers!)

SpargDD

-min temp:  49.9 F

-max temp: 85.9F  

-start date: Jan 1

-sensor location: canopy height

-sensor location: flooded when vines are flooded, under ice, always there

-sensor location: shielded

Towards A Better DD Model for Cranberry Pests, Shawn Steffan

The Steffan lab has produced a thorough model for Sparganothis Fruit Worm growth stages, and this is the source of the SpargDD Harmonization Task Force project above. New directions for the work include a conversion factor from vine canopy temperature to dike temperature. Current data indicate that northern WI canopy temperatures are 11% cooler than vine temperatures, while central WI canopy temperatures are 15% cooler than dike temperatures. Future research will compare hourly DD accruals with a horizontal cutoff method, to the sine wave DD accrual with horizontal, vertical, and intermediate cutoffs.

Introducing Steven Hall, Steven Hall

New UW-Madison faculty member Steven Hall focuses on soil, water, and climate change mitigation.

                -water used for cranberry production often has high nitrogen and phosphorus even before it enters the cranberry marsh

                -marshes and adjacent lands may provide opportunities for chemical and biological retention and removal of these nutrients

                -with careful and creative water management, cranberry marshes might be able to improve regional water quality

Dr. Hall  is looking forward to meeting and working with cranberry growers, and can be reached at steven.hall@wisc.edu .

This article was posted in Cranberry and tagged Allison Jonjak, Cranberries, Spring Mini clinic 2024.