There are a few new fungicides that either just came out or that came out last year. We need to make sure that we incorporate these materials in a way that will allow for optimum efficacy and resistance management. We will be discussing these products in meetings, but as an update for your planning purposes, the following are on the list.
Cevya [FRAC 3; DMI]. This DMI fungicide was registered for use last year by BASF. It is a good DMI product, but I would treat it like any other DMI that is out there at this point. It is in the same basic category relative efficacy as Indar at the high rate. It is not as active as Merivon. As with other DMI materials, I like to see it applied only in the late-season brown rot sprays; I also would want to see it follow the applications with products like Merivon or Luna Sensation — FRAC 7 [SDHI] + 11 [QoI]. It is a good product for just before or even during harvest if necessary (12 hr REI and 0 PHI). Based on our trials, it is likely subject to DMI resistance — just like the other DMIs, so use it with care. Ideally, I would not want to use DMIs more than once or twice per year and only in the late season.
Miravis [FRAC 7; SDHI] and Miravis Duo [FRAC 3 + 7]. These products are both from Syngenta. Miravis and Miravis Duo are extremely active against peach scab, and they provide brown rot control that is comparable to Merivon or Luna Sensation. If scab is not being controlled in your petal fall and shuck split applications with chlorothalonil (e.g. Bravo and generics), then you might consider targeting these new fungicides at those application timings. However, I especially do not like the idea of using a DMI [FRAC 3] in the early-season applications — due to the potential for resistance development in the scab and brown rot fungi. The same is true for SDHIs (e.g. Miravis) and QoIs (e.g. Abound), but at this point, I do think resistance development is less likely with these for both scab and brown rot, as compared to the DMIs. Again, if you need these for early-season scab control, they are awesome. Miravis fits well with our rotation schemes for resistance management in the late-season brown rot sprays, but the DMI in Miravis Duo is not ideal for rotation. Again, we will discuss the nuances for our recommendations in our meetings, so stay tuned.
Chairman [FRAC 3 + 12]. This is another product from Syngenta. It is a post-harvest packing line product that is similar to Scholar, also from Syngenta. In fact, it is basically Scholar + propiconazole (a DMI). The addition of the DMI provides potential sour rot management. We have observed sour rot in some field locations over the last few years. This would be the last chance to manage sour rot as the fruit goes to market, so you might consider this product over Scholar if that is a concern. Chairman may also possibly broaden brown rot efficacy. Otherwise, I think that is all that Chairman brings to the table as compared to Scholar.
I hope you are all staying well, and I look forward to seeing you in person or virtually as the year progresses. As always, contact your county agents if you have questions about any of these newer products or other issues.