© mara_lingstad

When it comes to dollar spot control, strobilurin fungicides haven’t historically been among the first chemistries to come to superintendents’ minds. But now, Pinpoint, a strobilurin from Nufarm and Valent, stands to change that.

Registered for use in the United States and Canada, Pinpoint defies turf managers’ long-held expectations of strobilurins, effectively treating dollar spot while managing the pathogen’s resistance to other fungicides and improving golf course turf.

Researchers have consistently controlled dollar spot with Pinpoint over the last 10 years on bentgrass, annual bluegrass and other grass types at universities and golf courses, says Dr. Jason Fausey, technical director at Nufarm. “It has a lot of characteristics of the strobilurins, but then, especially for guys in the Midwest, the Northeast, where dollar spot is such an issue, it really is a new option for dollar spot control as far as a new mode of action to rotate to,” he says.

There is concern about dollar spot developing resistance to succinate dehydrogenase inhibitor (SDHI) fungicides like it has with other fungicide classes. Now superintendents have a new tool to help manage resistance, says Dr. Joe Chamberlin, product development manager at Valent. “Wherever dollar spot is your primary pathogen, this product, Pinpoint – mandestrobin – offers an opportunity to rotate a different mode of action with the SDHI fungicides, and really conserve the activity of both, because we don’t just want to manage resistance to SDHI inhibitors; we’ve got to manage it to strobilurins, as well,” he says.

Fungicides in another class, demethylation inhibitors (DMIs), control dollar spot, but severe summer heat often amps up their growth regulation properties, so rotating Pinpoint with DMIs gives superintendents the ability to manage dollar spot even under times of stress, Chamberlin says.

Growth regulation caused by DMIs often poses major setbacks for turf managers throughout the middle of the summer, says Todd Hicks, turfgrass pathology program coordinator at The Ohio State University. “A lot of times that whole family is gone for you, and you’re left with the few remaining products when dollar spot is at its worst and you’re trying to hold it at bay,” he says. “Well now you’ve got a product that’s in a totally different family. It’s like having a brand-new tool in the toolbox.”

Dollar spot has developed resistance to DMIs and Thiophanate-methyl, which makes Pinpoint a useful fungicide to rotate with, Hicks says. Additionally, turf managers are limited in the number of applications they can make of both contact and SDHI fungicides, so the product is beneficial in those scenarios as well.

In a trial, Clemson’s Dr. Bruce Martin saw positive results with Pinpoint. Top: Untreated. Bottom: Taken 28 days after fourth application.
© Dr. Bruce Martin, Clemson

Ohio State researchers tested Pinpoint for about 10 years, starting when the fungicide was known as its numbered compound, Hicks says. In their trials, they saw results throughout 14-21-day rotations.

Pinpoint sets itself apart from other strobilurins because it is labeled specifically for dollar spot control, while other strobilurins aren’t, Hicks says.

The product doesn’t need to be mixed with others because it creates results by itself, Fausey says. “It really is a new option for dollar spot control as far as a new mode of action to rotate to, because a lot of the times, traditionally with strobilurins, you would tank mix it with another fungicide for dollar spot control, whereas with Pinpoint, you won’t have to do that.”

One situation in which superintendents would want to tank mix Pinpoint with another product is when dollar spot has already appeared and needs to be treated curatively, Chamberlin says. On bentgrass greens far South, for instance in areas such as Georgia, curatively treating dollar spot is difficult to do during the summer. “You want to avoid curative control of diseases, period,” he says. “But we also know how the real world is; sometimes you don’t get out ahead of them, and you do need to respond curatively.”

Pinpoint controls dollar spot throughout both a large geographic range and multiple seasons, Fausey says. “I really look at it as a product that you can rotate into a current program anywhere from early spring to late fall,” he says.

Dollar spot appears in the spring and fall in the South, Chamberlin says. “It tends to like somewhat cooler weather, and so it’s very often the first pathogen that superintendents really see to any significant degree,” he says. “But you don’t typically have other pathogens present early spring, late fall, and that’s when dollar spot would be your primary pathogen of concern.”

While applying Pinpoint by itself will take care of dollar spot in the spring and fall, Chamberlin says superintendents should rotate it in the summer with products that fight other diseases.

Like in the South, dollar spot is one of the first spring pathogens to appear in Ohio, Hicks says. “The difference is, on the other pathogens that show up in the spring, a lot of them lessen or go away as the summer progresses, where dollar spot increases over the summer,” he says.

The product will benefit superintendents. “Having a new addition like this that’s viable is a big bonus if you’re a turf manager.” Hicks says.