[Archivist]

Agriphage for Fireblight Control (PDF of archived thread)

[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.

[Brittany Kordick]

Just getting into shoot blight season down here in North Carolina, so for us that means AgriPhage is in the spray mix again. We try to send in anything new to us, spray material-wise, that we might be interested in tank-mixing with AgriPhage to OmniLytics for compatibility testing. We just got word back that Botrystop, an OMRI-listed fungicide labelled for fireblight, as well, is completely compatible with AgriPhage. We’re in the process of having Madex, the viral formulation targeting codling moth and Oriental fruit moth, tested, as well, and will update this thread when we have the results back on that.

[Brittany Kordick]

All right, Madex is compatible with Agriphage. Keep in mind with all these supposed compatibilities, though, that the testing Omnilytics does for us checks to see whether or not a material is compatible with Agriphage, not vice versa. So we’ve established that nothing about the Madex granulovirus formulation deactivates or interferes with the efficacy of the bactericidal qualities of Agriphage. We do not know whether Agriphage has any adverse effects on Madex if tank-mixed together or applied in quick succession; that testing would have to be done by the Madex manufacturer, in this case Certis. This goes for all the materials we’ve reported as testing compatible with Agriphage over the years: we’ve established that their tank-mixing with Agriphage does not cause adverse effect to Agriphage, but that doesn’t necessarily mean that Agriphage doesn’t cause adverse effects to any of these materials in turn when tank-mixed. Just in case folks don’t realize that compatibilities are relative to the material being tested, occurred to me that this might need to be spelled out somewhere.

[Brittany Kordick]

Been meaning to add some seasonal updates regarding Agriphage for the past few months. See below for more details, but the skinny is:

Be aware that there’s a new compatibility list for Agriphage on the product website.
Agriphage is compatible with Nufilm-P and Regalia.
Agriphage is very perishable — use it up quickly after opening.

As you may have seen on the Agriphage website, OmniLytics maintains a pretty good compatibility list. However, that list is a bit different from the older one we referenced until recently. I think it was Nufilm-P that put up a red flag for us earlier in the year. We love Nufilm-P for most of our other biological spray components and thought that it might really help with the high UV sensitivity of Agriphage. I was personally nervous about mixing the two, however, wondering if the spreader sticker might affect the replication of the phages. My mother overruled me, having referenced the old compatibility printout we’ve been using and found that Nufilm-P was just fine. Yet the newer compatibility list on the website did not list Nufilm-P one way or another.

We called in and were told that Agriphage does occasionally update their phage cocktail slightly to prevent issues of resistance. While the “other materials” in the formulation don’t change, the individual phages may. So they’ve been in the process of retesting materials for compatibility with the current version of Agriphage and are updating their website list (our old printoff is good for guidance, but it is essentially obsolete now). We were told that they really haven’t seen a lot of changes in compatibility and don’t expect to, but that they just want to be extra cautious and do the proper testing to be sure. They do know that Nufilm-P is just fine with Agriphage and highly recommend using them together. (So do we after using it this season; we feel like we got our highest Agriphage efficacy ever this year and credit that to the Nufilm addition keeping the phages protected from UV degradation longer).

A question also arose this season regarding Agriphage compatibility with Regalia. We don’t use Regalia on our apples, but we do use it in our small pear orchard, and we’ve always tank mixed it with Agriphage if need be. After we learned what was going on with the compatibility testing overhaul, we checked the website compatibility list and saw that there’s no Regalia listed anymore. But like the Nufilm-P, our older list stated compatibility with Regalia was fine at a certain rate. We called in again and were told that they haven’t gotten around to retesting Regalia yet, but they’d really like to since they know so many growers might overlap usage with Agriphage. We sent in a sample a week or so later for testing and subsequently heard back from the OmniLytics lab that “Regalia is completely compatible with Agriphage.”

Last point: ever open your Agriphage jug and get a rank off-odor? We have, but somehow never got around to asking OmniLytics about it until this spring. Turns out that the medium the phages are formulated with is very easy to contaminate. As in, you want to use Agriphage up as soon as possible after opening because other organisms will completely take over and outcompete the phages. We considered buying some quart containers of Agriphage as a result, just so that when we need a bit more to finish a spray, we don’t have to open a 2.5 gallon jug and potentially let it sit and spoil, but the price for quarts vs. 2.5 gallon jugs was too high for us to consider. Now we just do our best to use up open jugs quickly (if there’s going to be a half gallon left after a spray, might as well divide it amongst tanks) and likewise, we might reduce our rate slightly if we’d otherwise have to open a new jug and take a half gallon out only. And if we smell an off odor in any leftover Agriphage, it doesn’t get used.