We asked BASF a few questions about dollar spot. Learn what the symptoms of dollar spot consist of, how applications should be managed, and what challenges we are facing when controlling this disease.

What are the symptoms of dollar spot that we must look out for?

Symptoms on individual leaves express as tan/white, hour-glass shaped lesions. As a collective of leaves, symptoms include small circular tan/white circular ‘patches’ (.5”-2” in diameter) the size of a silver dollar. Hence the name dollar spot.

When should applications for the disease begin?

Starting early and staying ahead of dollar spot is key as part of season-long success. There are many predictive models than can help. First chemical apps would begin around the second mowing of turf. Air temperatures around 60 degrees with soil temps around 55 – 65 degrees. This will very based on geographic location. Finishing the season strong with late-season fungicide applications is critical as well as dollar spot overwinters and can survive until the following spring. Emerald® fungicide from BASF is an excellent choice to start and finish the season.

What should you do if you miss your first application for dollar spot?

Don’t miss it!? An ounce of prevention is worth a pound of cure rings true for almost all turfgrass diseases. If you do miss, make sure to use a fungicide that has strong curative/knockdown activity. BASF has several great products – Maxtima® fungicide, Xzemplar® fungicide, Navicon® Intrinsic® brand fungicide, and Lexicon® Intrinsic brand fungicide – that have curative and preventative control of dollar spot. The BASF Intrinsic brand fungicides  (Honor®, Insignia®, Lexicon, and Navicon) can help turfgrass recover from symptoms due to the proven plant health benefits those products provide.

How many applications do you recommend we make to manage dollar spot and when?

This will vary based on geography, application intervals, and many other factors. Some superintendents will make 6-8 applications, and others might make 12-16 applications.

One point to note – when building fungicide programs make sure to use multi-site compounds such as ArmorTech Rotator fungicide (fluazonil) and chlorothalonil containing products and compounds with different FRAC codes to avoid resistance. BASF has several excellent dollar spot fungicides across several different FRAC codes to build an excellent dollar spot fungicide program.

What are the challenges we face when controlling dollar spot?

Fungicide resistance can be a challenge with dollar spot. Two of our great fungicides, Maxtima and Navicon, both contain a DMI that is excellent on dollar spot (even on DMI-insensitive pathogens) and can be used in the heat of the summer without the negative effects of traditional DMI’s.

Extended periods of wet overcast weather can be a challenge. Cultural practices such as aerification, vertical mowing, and topdressing to help reduce thatch and maintain balanced moisture are key to any healthy turfgrass.

Fertility deficiencies can also aggravate dollar spot problems, so a balanced fertility program is also essential.