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Spring Showers bring Primo/Proxy

April 5, 2010

Above average temperatures swept across much of the state last week making it feel almost like summer at times. The turf seems to be responding nicely to the favorable conditions as new growth begins to take the edge off some of the scars left from the winter season.

The relatively dry weather as of late has helped speed the rise in soil temperatures and I spotted some prostrate knotweed germinating through the cracks in my driveway. Prostrate knotweed is a summer annual and usually the first annual weed to germinate in the spring. Like many weeds, knotweed thrives in compacted areas and is often found along the edges of sidewalk and cart paths.

Early spring also marks the time of year for applications of primo/proxy. Primo and proxy are both growth regulating compounds designed to slow the growth of plants. Used together in a tank mix this combination of products provides a synergistic effect to inhibit seedhead formation on poa. Inhibiting seedhead formation of poa has two main advantages. First, the flush of seedheads in the spring can be unsightly and interfere with the uniformity of the playing surface. Second, producing seedheads requires an expenditure of energy from poa which is already susceptible to many biotic and abiotic stresses. Inhibiting seedhead formation helps conserve energy within the plant (poa) which will hopefully leave it with more reserves later in the season when pressure from diseases and other stresses are higher.

The effectiveness of the primo/proxy application depends largely on proper timing. While doing my research on this topic I discovered a variety of ways in which superintendents try to properly time their applications. Some track and use growing degree days, some apply once full green up has been achieved (this is usually after the second mowing), others monitor and apply when poa is nearing the boot stage, and still others try to time their applications based on historical data of poa seedhead development. Whichever method you prefer it is important to apply before you see the seedheads. A repeat application in 14-21 days is often recommended. As always, remember to review the label before any application.

Of course the other big news this week is the start of The Masters Tournament. In case you weren’t in the mood for golf this should help. Here is a picture to wet your appetite.

Marcus Jones
Graduate Research Assistant

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It’s the Start of Another Season...Almost

March 11, 2010

Winter has eased its grip on the Midwest the last 10 days or so and we have experienced significant snow melt throughout much of Iowa. Grass is even starting to peek through the snow in spots. Could this be a sign spring is right around the corner? Before we get ahead of ourselves, let’s recap the Iowa winter thus far.

Snowfall for the three mid-winter months of December, January, and February averaged 45.1 inches or 23.3 inches greater than normal. This is the greatest snow total of record for these three months (old record of 44.7 inches Dec. 1961-Feb. 1962). The snow total for the overall snow season (fall through spring) ranks 8th highest among 123 years of record with another two months of the season remaining (keep in mind that Punxsutawney Phil saw his shadow for what it’s worth). This has been the third consecutive colder than normal winter and fourth consecutive snowier than usual winter.

But, with the recent snowmelt, I was able to escape from the office for a little scouting on the golf course. With the prolonged snow cover and soil temperatures right around the freezing mark I was anticipating decent snow mold activity. The location I was scouting had been treated with a snow mold preventative but I was still able to find small breakthroughs of both gray and pink snow mold.

Most of the gray snow mold appeared in the rough areas and the damage is likely only superficial. Gray snow mold initially appears as circular patches ranging in color from light yellow to white soon after the snow melts. As the disease progresses the patches can grow and coalesce together with the leaves often becoming matted together. A reliable way to identify gray snow mold is to look for sclerotia embedded in the leaves of infected tissue. The sclerotia appear yellow to light brown soon following snow melt and eventually turn dark brown.

Pink snow mold, as its name implies, is often identified by white to pinkish mycelium that forms at the margins of the patches. The pink color is brief and often only visible during early daylight hours. I only saw two patches of pink snow mold during my outing. However, the window for pink snow mold development extends further in the spring as snow cover is not a requirement for this disease.

I also was treated to some vole damage. Voles are small rodents (4 to 6 inches) long and are mainly vegetarians. The main damage to turf is caused by their runways through the turf canopy. Vole damage is common under snow cover as they search for seeds and other vegetation.

Hopefully you’ll be greeted with healthy turf as the snow continues to melt. Let’s hope spring is just around the corner.

Marcus Jones
Graduate Research Assistant

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