Get Yer T-T's Out! (and use them for summer disease control)

¡Anthracnose Está Aquí!
I just got back to Washington DC from California where I had a great time at the GCSA of Southern California's Annual Scholarship and Research Tournament (more about that next week though!).

This week, we started to get a good number of anthracnose samples on both annual bluegrass and creeping bentgrass at UCR. It's a little early for full blown anthracnose season, but keep your eyes out for the disease; especially on annual bluegrass putting greens. Apply adequate nitrogen, keep on top of your sand topdressing, and start your preventive fungicide programs if you already haven't started.

Other diseases worth mentioning would be fairy ring and southern blight (Sclerotium rolfsii); both of these diseases seem to be active in California right now (seen, reported or diganosed), including right on top of my dollar spot experiment at UCR (damn it).

New DMI-Fungicides for Summer Disease Control on Cool-season Turf
'T-T's? Yeah, I know, it’s a bad pun, but I just wanted to give a quick update (and possibly clear up some confusion) on some new DMI-fungicides on the market that oddly all have 'T' in the name and could be useful for summer disease management, focusing on their utility on diseases of cool season turf. Trinity (BASF), Triton (Bayer), Tourney (Valent) and Torque (Cleary Chemical) are all new DMI-fungicides that are or will soon be registered for use for turfgrass control in the U.S.

All DMI-fungicides work by interfering with fungal cell membrane biosynthesis; specifically by interfering with demethylation of an ergosterol precursor (don't let me geek out on you guys here). Because of this extra methyl-group sticking out of the ergosterol, the cell membranes in fungi don't assemble together properly and voilà, the fungal membranes break open and the fungus dies.



You can see this in the pictures above (via Bayer Crop Science) of the untreated (top) and DMI-treated fungi (bottom).

Oomycetes like Pythium and downy mildews, don't use ergosterol in their cell membranes, so while DMIs are pretty broad spectrum against most major turfgrass diseases like dollar spot, brown patch and anthracnose, they won't touch oomycetes.

Like all other DMIs (Banner MAXX, Bayleton, Eagle, Rubigan), these new fungicides are systemic (acropetal penetrants) and have significant post-infection activity vs. fungi. Although I'm talking about these new 'T' named DMIs – remember that each of the DMIs is unique and some work better than other vs. certain diseases, and I'm not necessarily saying you should throw out your old ones in favor of these new fungicides!

Also – just a reminder, DMIs also tend to cause some injury on turf when used at high rates or repeatedly, so be careful when using these and stick to the label recommendations. Of special consideration is using these on warm season turf, on annual bluegrass putting greens and in combination with plant growth regulators. I'm not pointing fingers at anybody, but read up on the label just to save yourself any unnecessary summer grief when using DMIs.

* Check with your local distributor or manufacturer representative on availability for these products; my first hand experience with these comes from California, and as you know California and New York are typically the last places for new pesticides to get state registration and approval.

Trinity Fungicide (active ingredient: triticonazole)
BASF's Trinity fungicide has been registered in a number of states and recently received a California registration. It comes as a liquid containing 1.69 lb of triticonazole per gallon of product and use rates go from 0.5 to 2 fl oz per 1,000 sq ft (limited to 1 fl oz in California) and the fungicide controls many of the major turf summer diseases such as dollar spot, anthracnose, brown patch and summer patch. Trinity also has good activity vs. brown ring patch (aka Waitea patch), and is labeled for suppression of algae, which can use useful for the control of this problem on putting greens. See http://betterturf.basf.us/ for more info on Trinity.

Chipco Triton Flo and Triton (active ingredient: triticonazole)
Bayer Environmental Science's Triton fungicides share the same active ingredient as BASF's Trinity but differ in their formulations. Chipco Triton Flo is a liquid containing 3.1 lb of triticonazole per gallon (thus lower labeled use rates as compared to Trinity) and is formulated with Bayer's StressGard pigment (which is an added bonus for cool season turf in the summer). Chipco Triton Flo use rates go from 0.28 to 1.1 fl oz per 1,000 sq ft. On the other hand, Triton comes in a dry formulation containing 70% triticonazole (use rates of 0.15 to 0.6 oz per 1,000 sq ft) and does not contain the StressGard pigment. Both fungicides control summer diseases like dollar spot, anthracnose, brown patch and summer patch as well as brown ring patch (and have algae suppression on the label). Currently, the Triton label is broader than the Chipco Triton Flo label but I expect that to change as Chipco Triton Flo nears registration throughout the U.S. It's not clear to me if Bayer intends to have both fungicide formulations on the market at the same time or if the pigmented form with StressGard will phase out the non-pigmented one. See http://www.backedbybayer.com for more information on Triton and Chipco Triton Flo

Tourney Fungicide (active ingredient: metconazole)
Valent Professional Products Tourney is now labeled in most of the U.S. including California and New York. It comes as a dry formulation containing 50% metconazole, and has use rates of 0.18 to 0.44 oz per 1,000 sq ft. Like the previous fungicides discussed above, Tourney is effective vs. dollar spot, anthracnose, brown patch, summer patch and brown ring patch, but has a slightly more expansive label that includes summer trouble makers such as fairy ring and gray leaf spot. See http://www.valent.com/professional/index.cfm for more info on Tourney.

Torque Fungicide (active ingredient: tebuconazole)
Cleary Chemical recently secured tebuconazole for use for turf disease management. For a long time, you could buy it in the home and garden section of your local hardware store for lawn disease control, but previous attempts to get it registered for professional use through the EPA were 'difficult' at best. Torque comes as a liquid containing 3.6 lbs tebuconazole per gallon and is labeled for use at 0.6 fl oz per 1,000 sq ft. The label includes summer diseases such as dollar spot, anthracnose, brown patch, summer patch and gray leaf spot and is effective vs. brown ring patch. Registration is limited for now to just 26 states that includes Washington and Oregon in the West (but not California, Arizona, Nevada, Hawaii or most of the other states west of the Rockies. I would note that our research at UCR showed that tebuconazole and propiconazole (Banner MAXX) were the most intrinsically active vs. anthracnose, making these two very useful DMIs vs. this disease. See http://www.clearychemical.com for more info on Torque.

I'd really like to hear some feedback from you guys on how these new DMIs (and older ones) are working for you now or how they worked for you last year. Lemme know what you think!

Signing off from the right coast until next week.....