Get Ready for Anthracnose in the West

Sadly, Farrah Fawcett passed away from cancer today at age 62. I bet you that just about anyone who was a teen in the 1970s had a poster (like the one to the left) in their room.

We probably invoke her name at least a dozen times a week here at UCR since we work in Fawcett Laboratory. Often, when explaining where to send samples, we tell people that: "it's Fawcett Lab, as in Farrah Fawcett" - which often goes right over the heads of those superintendents in their early- and mid-20s. For that matter, many John Holmes references - in relation to optimal root length - also go over those guy's heads too. I have got to stop using 70s-pop culture references so frequently here in our lab.


Anthracnose Management
Here in the west, anthracnose is starting to pop up more frequently in the UC Riverside diagnostic lab. It could signal the start of the anthracnose season already. Although anthracnose can pop up on just about any cool season turf species, it's impact is very different on different species being used for different purposes on the course.

For perennial ryegrass, the presence of anthracnose often signals low fertility, heat and drought stress. Here, anthracnose is usually just a secondary pathogen affecting stressed turf. It usually does not warrant control directly, but does often indicate that cultural conditions need improvement in these areas.

On creeping bentgrass, we typically see anthracnose on greens that are "lean and mean", especially when there is high humidity and overcast days. Again, in these cases, anthracnose is usually not the primary cause of damage but does signal that fertility needs to be increased and plant stress reduced. Typically, shutting anthracnose down with a fungicide application or two followed by increasing the fertility will solve the issue.

On annual bluegrass though, anthracnose is a real killer because its often the disease that puts the nail in the coffin for Poa greens.

Check out our presentation on chemical control options for anthracnose here: http://www.turfpathology.ucr.edu/Downloads/anthracnose_chemical_control.pdf

as well as the cultural management practices for anthracnose research being spearheaded by the group at Rutgers
http://www.turf.rutgers.edu/research/usga-anthracnose.pdf

Sucessful anthracnose management on annual bluegrass greens in the West should combine cultural practices like adequate nitrogen fertility and water management with a sound preventive fungicide program.

With regard to fungicides for anthracnose - there are plenty of ways to skin a cat, but in a nutshell - here's what has been effective for us in trials conducted over the past few years.

Early season preventive DMI applications (especially Banner MAXX) should be initiated before soil temperatures exceed 70F (65-68F is usually a good starting place).

Chlorothalonil fungicides, Medallion and Endorse are good choices for control when air temps are high and the risk of negative PGR effects of the DMI-fungicides are present (see Lane's recent entry on the DMIs). These should be applied at 14-day intervals in the summer.

Chipco Signature can be tank mixed with the fungicides listed above for added control and stress reduction. Although the mechanism for stress reduction provided by the combination of pigment and fosetyl-Al in Chipco Signature is still not fully understood, I'm going with the theory that it's "sunblock for Poa". Although results from trials in the east have shown a direct effect of phosphonate type fungicides on anthracnose - our trial results from California have shown that Chipco Signature applied by itself isn't very effective versus anthracnose and needs a good partner to maximize the effectiveness of the tank mix application.

Finally - I don't mean to kick a dead horse, but QoI and benzmidazole resistance appear to be pretty common for anthracnose in areas that have used them exensively for anthracnose control. Monthly applications of Heritage or Insignia are still very important for summer patch control in the summer, but don't rely on them exclusively for anthracnose control.

In Other News...
Brown Ring (Waitea) Patch was reported from Minnesota and diagnosed from Montanta this week. It sounds like this disease is continuing to pop up throughout many places in the U.S.

Signing Off from the Left Coast!