Agriphage for Fireblight Control

  • January 22, 2024 at 8:53 pm #503

    Agriphage for Fireblight Control (PDF of archived thread)

    April 9, 2024 at 3:36 pm #1898
    Brittany Kordick

    Just in time for fireblight season 2024 we recently asked OmniLytics to test compatibility on some materials in our orchard management plan this season. Firstly, we realized we’ve never asked them to test seaweed before, and given that some minerals cause issues with the phages, thought it would be wise to know for sure that we’re good with Maxicrop seaweed (@ 1-2 lbs/100 gal), instead of just assuming so. We also asked them to test Stargus at a rate of 1-2 quarts per 100 gallons. Finally, we have been using biodynamic paste (not homemade, but the actual Josephine Porter Institute formulation) to treat neonectria cankers in our orchard, but have been hand-spraying the cankers with concentrated AgriPhage before slathering with the BD paste (not thinned with water at all) as insurance in case any of the cankers we’re treating are, in fact, fireblight-derived, rather than from neonectria infection. We suspected that something in the BD paste would probably not be compatible with the phages in such application conditions (again, thinking of mineral content, primarily). OmniLytics did a great job of trying to simulate our field application scenario as best they could in the lab — they “covered a petri plate with a thin film of purified phages on the surface (no host for replication) with the mud for 24 hours to simulate being covered.”

    The results:

    Maxicrop Seaweed = compatible out to 24 hours
    Biodynamic Paste = compatible out to 24 hours (and notably, concentrations of the phages did not drop at all after being covered with the paste for that long)
    Stargus = somewhat compatible — compatible at 4 hours, but slowly dropped the concentration of phages, ultimately missing the 24 hour compatibility mark. Therefore, OmniLytics advised spraying Stargus + AgriPhage immediately after tank-mixing for best results

    Sidenote: unsurprisingly, Blossom Protect/Buffer Protect is something orchardists might be keen to tank-mix with AgriPhage during blossom blight season, using the AgriPhage to wipe out existing Erwinia whilst simultaneously setting up subsequent protection in the blossoms with Blossom Protect. We’ve never combined the two products before, but thought there was a chance we might have occasion to do so this season, thus also queried OmniLytics about this scenario. They are very familiar with Blossom Protect and were able to give some good guidance re: combined usage with AgriPhage. There is a compatibility issue, but it is with the Buffer Protect additive that is usually combined with Blossom Protect to provide very acidic conditions that are inhospitable to E. amylovora. You definitely do not want to tank mix AgriPhage, Blossom Protect, and Buffer Protect (on the off chance that you do not purchase the Blossom/Buffer Protect kit, but only apply the Blossom Protect yeast formulation, you’re fine); the low pH is fatal to the phages. Our next question was, OK, if that’s the case, what if we applied AgriPhage and Blossom/Buffer Protect separately? OmniLytics’ advice in this scenario either to apply AgriPhage first, give it 1-2 days to work, then follow up with Blossom/Buffer Protect OR that you could apply AgriPhage as soon as the Buffer Protect was allowed to dry.

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