Apple Disease Update: Glomerella End Game

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Pre-harvest Glomerella Considerations

Image of Glomerella

With ‘Gala’ apple harvest soon approaching in Western NC, it’s a good time to review fungicide application schedules prior to harvest. While it might be extremely inconvenient to diversify fungicide programs based on cultivar harvest date, adapting cultivar-specific fungicide programs for Glomerella-susceptible cultivars may save a lot of heartache (and money) during storage.

Glomerella Susceptible Cultivars 14 days prior to harvest:

Plan A:

  • ~14 days out: Captan 80WDG 3.75lb/A (or 4L 2.5 qt/A) + Prophyt 4 pts/A
  • ~7 days out: Merivon 5.5 floz/A + Captan 80WDG 2.5 lbs + Prophyt 4 pts/A
  • ~Day of Harvest: Merivon 5.5 floz/A + Captan 80WDG 2.5 lbs + Prophyt 4 pts/A

Plan B:

  • ~14 days out: Captan 80WDG 2.5 lb/A + Ziram 3 lb/A
  •  ~7 days out: Merivon 5.5 floz/A + Captan 80WDG 2.5 lbs + Prophyt 4 pts/A
  • ~Day of Harvest: Merivon 5.5 floz/A + Captan 80WDG 2.5 lbs + Prophyt 4 pts/A

Plan C:

  • ~14 days out: ~ Merivon 5.5 floz/A + Captan 80WDG 2.5 lbs + Prophyt     4pts/A
  • ~7 days out: Captan 80WDG 3.75lb/A (or 4L 2.5 qt/A) + Prophyt 4 pts/A
  • ~Day of Harvest: Merivon 5.5 floz/A + Captan 80WDG 2.5 lbs + Prophyt 4 pts/A

Glomerella Susceptible Cultivars more than 14 days from harvest:

  • Application of Captan 80WDG 3.75 lb/A (or different formulation equivalent)+ Prophyt 4 pts/A OR Captan 80WDG 2.5 lb/A + Ziram 3 lb/A on a 7 to 10 day  interval has worked well for us. If flyspeck/sooty blotch, or bot rots are a concern, you may want to include Inspire Super, Topsin (or different t-methyl product), or Aprovia tank mixed with Captan + Prophyt. Keep in mind, Inspire Super, Topsin, or Aprovia applied alone will NOT provide adequate control of Glomerella leaf spot or fruit rot.

 Cultivars not-susceptible to Glomerella:

  • -Scout the orchard. If little to no rot is present, you might be able to get by on a 14 day interval (depending on rains). Inspire Super, Aprovia, Topsin (if no resistance), Merivon, Luna Sensation can be applied to control other rots, however mix with ½ rate of Captan 4L or Captan 80WDG for resistance management. Merivon applied on day of harvest might help keep rots down in storage.