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Dollar Spot and Anthracnose Q&A with BASF

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We asked BASF a few questions about dollar spot and anthracnose. Learn what the symptoms of dollar spot and anthracnose consist of, how applications should be managed, and what challenges we are facing when controlling these diseases in this Q&A.

Dollar Spot

What are the symptoms of dollar spot that we need to 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. BASF’s Emerald is an excellent choice to start and finish the season.

If you miss your first application for dollar spot control, what should you do?

Don’t miss it! 😊An ounce of prevention is worth a pound of cure rings true for most 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, Xzemplar, Navicon, and Lexicon that have curative and preventative control of dollar spot. The BASF Intrinsic products (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. Our two newest fungicides, Maxtima and Navicon, both contain a new 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 essential as well.

Anthracnose

What are the symptoms of anthracnose that we need to look out for?

Anthracnose can be a foliar blight or a basal rot disease. It predominately attacks annual bluegrass but can infect older varieties of creeping bentgrass. Anthracnose can occur throughout the growing season but is most common in the summer when the turfgrass is under stress.

The foliar type shows on individual leaves as small brown or yellow even orangish cast and does not have the vigor of a healthy plant. The basal type occurs when the pathogen infects the crown of the plant. The basal rot anthracnose typically kills turf and thinning of turf is prevalent. Both types produce black acervuli that can be seen with a hand lens or microscope.

When should preventative applications for the disease begin?

As soon as possible but especially before the summer stress begins. BASF Intrinsic Brand Products (Insignia, Honor, Lexicon, Navicon) are excellent choices as they provide proven plant health benefits to bolster the plant and help the plant defend itself from ancillary stresses. Using these products throughout the summer stress provide benefits beyond fungicidal activity.

If you miss the preventative application for anthracnose, what should you do?

As said above – don’t miss preventative applications and take measures early to mitigate any stress on the plant. Once anthracnose is visible that plant is severely weakened and can be an uphill road to recovery. Remove as much stress on the plant as possible – raise mowing heights, alternate rolling mowing, use fans for air movement, light topdressing (do not brush in), and balanced fertility and irrigation to name a few. Utilizing the BASF Intrinsic brand products to provide a one-two punch of fungicidal activity and plant health will certainly help the recovery process. Maxtima and Navicon are two new DMI’s that are excellent on anthracnose and can be used in the heat of the summer without the negative effects of traditional DMI’s.

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

This will very widely based on geographic location and turf type but most will be in a 3-5 application range.

What are the challenges we face when controlling anthracnose?

The pressure to provide excellent playing conditions can be a challenge. The additional stress on a turfgrass plant can lead to problems that are not limited to anthracnose. Each superintendent knows the balance between plant health and conditioning at their properties.