Insects. Hopefully any spring bug issues have been managed by now. Koppert bumble bees arrived this week and migratory honeybees are starting to move into position.
The few green spanworm caterpillars that appeared this spring have pupated and a few have emerged as moths (in the lab) so you may start seeing them flying on the bog. Pheromone traps are up and first flight (biofix) of blackheaded fireworm, Sparganothis fruitworm and Cranberry fruitworm have been confirmed. However, most acreage that saw a Fanfare application will see very low (if any) flight activity of blackheaded fireworm and Sparganothis fruitworm. Cranberry fruitworm is another story – moths will be present on most bogs from mid-June to mid-July, but they will only lay eggs when the pinheads start to swell up. Plan your Altacor (or other chlorantraniliprole products like Osario or Turazi) for 50% out of bloom, likely 2 weeks off!!
Scale is causing problems for another year. If you have an active infestation, with orange dieback, and you can find live yellow/orange females under the protective covers, you should get ready to spray perhaps next week. Multiple sites checked show only the beginning of egg production indicating crawler development in a week (or so). The heat is pushing their development just like it is pushing the pods into flowers. You can bring samples into the Cranberry Station to have the scale stage checked. Ask for Krystal or Marty!
Weeds. Poison ivy is now fully leafed out. Spot spraying concentrated Callisto is the one of the best tools we have for managing this difficult weed. Our research shows that by mid-June, PI has invested stored resources on growing full-sized leaves, and that is the best time to make your first application (see Chart Book or contact me for more details).
While a single application may knock it back, two apps are needed to see significant control. After the PI recovers from the first treatment and spends more resources on making new leaves, treat it again (4 weeks or so later). Remember you can only make 2 applications of Callisto per bed per year.
Disease. The Final Keeping Quality Forecast for 2026 is VERY POOR. Fruit rot risk is expected to be high without timely and effective disease management. Your first application should happen when 10-50% of flowers are open. Once the fruit has set and begun to increase in size (mid-late July), fungicides are no longer necessary or effective for fruit rot management.
Timing Matters!
- Bloom is the critical infection window. Fungicide applications should be timed during bloom to protect open flowers against infection.
- Fungicides protect only tissues present at the time of application. Closed pods may receive limited to no protection, especially from contact fungicides.
Contact vs translaminar fungicides
- Contact/multi-site mode of action (chlorothalonil, mancozeb, coppers)
- Contact fungicides do not enter plant tissue and act only on the surface to protect against infection, no movement within the plant.
- Won't protect tissue that develops after spray occurs.
- Act on multiple biochemical pathways within the fungal pathogen, making them less prone to resistance development. They are often used in rotation with single-site fungicides to enhance efficacy and preserve the effectiveness of high-risk products.
- Translaminar/ Single-site mode of action (azoxystrobin, difenconazole, fenbuconazole, prothioconazole)
- Translaminar, sometimes also known as “locally systemic”. Can penetrate the plant surface but are not true systemic pesticides (cannot be taken up and translocated throughout the plant).
- Offers both protective and some curative activity during early infection periods (if applied immediately after infection).
- May offer some protection to developing tissues (closed pods) due to their translaminar movement but effectiveness still depends on timing and mode of action.
- These fungicides are targeted and act on a single-site, meaning they disrupt a specific point in a biosynthetic pathway in the pathogen. They are generally at medium to high risk for fungicide resistance development by fruit rot fungi.
- Often recommended to be mixed together in an application – e.g., FRAC 3 + 11, or 9+12 + 11.