Currently I'm participating in a leadership program led by Dean Garey Fox, and have learned that optimism is not necessarily my superpower. Indeed, as my friend and PhD advisor once told me, "The grass isn't always greener on the other side, it's just a different shade of brown". So for this week's post, I'm going to try to be optimistic of this extended epic drought we've been facing throughout the state: At least disease pressure, including Glomerella and bitter rot, isn't too high?

Looking at the forecast this week, the best chance of rain is on Saturday, and minimum/nighttime temperatures range from the mid 40s to mid 50s. Right now, I don't believe there's too much risk for a GLS or bitter rot infection event until Saturday, so consider waiting until Thursday or Friday to make a fungicide application. Remarkably, the lack of rain has also extended the apple scab season. As of April 20th, only 96% of ascospores, the primary infection spores of the apple scab pathogen, Venturia inaequalis have been released in Henderson County, NC. If we get rain on Saturday, 4/25, all primary inoculum should have been released. With the mancozeb and captan backbone for GLS and bitter rot management on 7 to 10 day application intervals, this should be enough to control any secondary scab infections (unless the rain decides to make up for lost time).

Given an early glimpse at next week's forecast (rain???) and the timing in the season (1st/2nd cover for most in NC), I would suggest by the end of the week you should have initiated 7 to 10 day fungicide application intervals if you have not yet done so. In addition, here are some considerations that we've learned through our trials:

• Mancozeb and captan, even at half rates (3 lb/A manzate; 2.5 lb/A Captan 80WDG), work well for GLS control
• Mancozeb should be applied up to its annual maximum allowed limits for the 3 lb/A rate (21 lb/A per season) within 77 day PHI
• Finish allowed manxcozeb applications prior to switching over to captan for the season (an exception may be for 'Red Delicious' where captan may be needed earlier for Alternaria leaf blotch management)
• FRAC 11 fungicides are most efficacious GLS and bitter rot control in North Carolina. Fungicides containing the FRAC 11 pyraclostrobin (Merivon and Pristine) performed better in our fungicide trials than fungicides containing the FRAC 11 trifloxystrobin (Flint Extra, Luna Sensation) for GLS control. For cultivars that have bitter rot, but no GLS symptoms, these fungicides performed similarly. The FRAC 11 fungicide, Sovran, in general has not shown as high of efficacy for GLS or bitter rot control in the southeast. Cabrio (pyraclostribin) is an option this year and will work similarly for GLS control as Merivon or Pristine.
• Some orchard blocks in western NC have populations of Colletotrichum fructicola (a species that causes GLS and bitter rot) that are resistant to the FRAC 11 (strobilurin fungicides). This means that NO FRAC 11 fungicides will be effective against bitter rot or GLS caused by this fungal species. In more specific terms, if you have resistance to strobilurins (FRAC 11s), Merivon, Pristine, Luna Sensation, Flint Extra, Cabrio, and Sovran will NOT be effective for GLS/bitter rot control.
• Aprovia is the only SDHI fungicide that we have evaluated to have efficacy against the Colletotrichum species causing GLS and bitter rot on apple in NC
• Omega fungicide at its highest rate has good to excellent efficacy against bitter rot. In our trial in 2025, Omega applied consecutively 10x from petal fall through harvest provided moderate control of Glomerella leaf spot in our 'Glomerella Gala' research block at the MHCREC. Omega applied with captan with be my "3rd choice" if an extended rain period is approaching with a FRAC 11 (Merivon, Cabrio, Pristine) + captan, and Aprovia + captan as my 1st and 2nd choices, respectively.
• FRAC 3 (DMI fungicides such as Inspire Super, Cevya, Rally, etc) do not control GLS and bitter rot in NC
• Starting around petal fall, applications must be made on a 7 to 10 day interval even if there is no rain. Leaf wetness matters when it comes to infection by the GLS fungus and the development of disease symptoms. When leaf wetness and conducive temps align, disease can occur.

As of April 20th, this week's forecast overall seems at a relatively low risk for GLS and bitter rot. However, next week, while cooler currently has a greater chance for precipitation. I'd consider spraying towards the end of the week, and consider the following options:

• Option 1: If you applied a FRAC 11 (strobilurin last week), consider manzate (3 lb/A) OR Captan 80WDG (2.5 lb/A) + Aprovia (7 fl oz/A)
• Option 2: If you didn't apply a FRAC 11 last week, consider manzate (3 lb/A) OR Captan 80WDG (2.5 lb/A) + Cabrio or Merivon or Pristine at their highest labeled rate.
• Option 3: If you are particularly concerned about Marssonina leaf blotch, consider consider manzate (3 lb/A) OR Captan 80WDG (2.5 lb/A) + Merivon, Cevya, OR Inspire Super. Aprovia and Cabrio are not strong against this disease and Captan and Mancozeb only have moderate activity.

Lastly, if you still have any open blossoms, a wetting event (dew, pesticide application, rain) will cause an infection Thursday, Friday, and Saturday. Consider including strep or Kasumin 2L in the tank to cover any late or rat tail bloomers. I would also consider making a second application of Kudos. Dr. Annie Vogel provided a fantastic recap of her research with Kudos in young trees last year, and it's certainly worth a read.