Well, green tip to pink bud (or to bloom in some cultivars and production areas) seemed to progress fairly rapidly again this year! this year! In this post, I've included the main diseases you should be focusing on for the tight cluster/bloom period. In next week's week's post I'll get more in depth into bloom fungicide and antibiotic applications, including when to commence Glomerella leaf spot management. In the upcoming days and weeks please keep your eyes out for Blossom Blight Infection Alerts. I know growers in Polk County already have full bloom in some cultivars and that flowers are opening in Pink Lady, Grannies, and early-bloom cultivars in the mountains.

New News!

To begin 2026, let's start with some fungicide updates!

1. Cabrio (pyraclostrobin, FRAC Group 11) is now registered once again for apple disease management! Pyraclostrobin in the strobilurin component in Pristine (pyraclostrobin + boscalind (FRAC 7) and in Merivon (pyraclostrobin + fluxapyroxad (FRAC 7). The rate is 9-12 oz/A; I would use the highest rate given the GLS and bitter rot pressure we have in the southeast. Since fluxapyroxad (the other component of Merivon) does not have activity against bitter rot or GLS in NC, but is strong against Marssonina leaf blotch, and good against apple scab and powdery mildew, I'd consider positioning FRAC 7 fungicides (such as Aprovia, Tesaris (fluxapyroxad), Luna Tranquility, Miravis, Excalia) earlier in the season and using Cabrio tank mixed with mancozeb or captan for bitter rot/GLS management- more of this in next week's post and at the "Winter" Apple Conference this Wednesday (3/25)
2. Our collective voices have been heard! A decision on mancozeb is not anticipated until late 2027 at the earliest. In addition, Ziram has not been canceled (as of today's post). Although Ziram quantities are limited this year, UPL tells me they are ramping up production for the 2027 season.
3. Axios (FRAC Group 52) is a relatively newcomer to the market for apple disease control. Trials conducted last year showed strong activity against powdery mildew and in other states, the fungicide has demonstrated excellent control of scab. This is a novel FRAC Group, so it gives you another weapon. Unfortunately the fungicide did not fare well in GLS/bitter rot trials or in Marssonina trials in NC in 2025.

During this time and continuing through petal fall, ascospores (spores that overwintered primarily on leaf litter) will mature rapidly. Once “ripe”, these spores will be released during a rain. Therefore, any green tissue not protected is susceptible to infection. In Edneyville NC, we initiated the model when approximately 50% of the buds on ‘Gala’ reached green tip (~ March 8, 2026). As of March 23, ascospore maturity is at 23% and there as been a cumulative ascospore discharge of only 8%. Given the dry week ahead of us, there are currently NO infection events in Henderson Cty are predicted from March 23-28, 2026.

If you had a powdery mildew problem in some of your blocks last year, since the pathogen overwinters in buds, the disease likely could be an issue again this year. Often, the first sign/symptom of powdery mildew in your orchard will be a white-silvery colored “flag” shoot that is stunted in growth as seen in the above photo. If you do see flag shoots, your first line of defense is to get them out the tree and out of the orchard. Multi-site protectant fungicides such as captan and mancozeb have marginal efficacy against powdery mildew, so if you are relying on these products for scab control during this period, be sure to slip a single-site fungicide into the mix. In general, stobilurins (FRAC 11) have performed well in our trials at MHCREC, but I’m hesitant to recommend them at this time of year because of GLS and Bitter Rot concerns later on. DMIs (FRAC 3) demonstrate a range in activity against powdery mildew (some work better than others) but I’ve generally observed excellent mildew control with Procure and Rhyme. Newer DMI chemistries such as Cevya and Inspire Super do a "good" job at managing mildew and are likely adequate for most situations here in NC. In general, SDHIs have performed fine to good in our field trials, but should also be adequate for mildew control at this time of year. Axios has also demonstrated good to excellent efficacy in trials.

This is also the time of year to start managing cedar apple rust. In general, an application of a DMI fungicide every other application should do the trick. As I've said previously, you don't need to break the bank to buy the newest DMI- Procure, Rally still perform well in our trials. No other fungicide groups labeled for apple diseases control provide moderate or high levels of efficacy against rust in apple.

In summary, here are some hopefully helpful tips as the long season of fungicide sprays commences:

• Mancozeb should be the backbone of your fungicide program at this point. The "half rate" (e.g. 3 lb/A) should be used.
• Consider a DMI (FRAC 3) fungicide such as Inspire Super or Cevya, a SDHI fungicide such as Aprovia or Miravis, or a DMI/SDHI premixed product such as Luna Flex in tank mixture with Mancozeb. Axios will also provide good control of scab and powdery mildew. If you don't apply a FRAC 3 this week, make sure to include one in your tank next week for rust control
• I would avoid using any strobilurins (FRAC 11) fungicides at this point. You will need these for bitter rot and Glomerella leaf spot control. Same deal with captan-hold off on it until you can no longer spray mancozeb.