Annual Bluegrass Weevil
Photo: B. McGraw

Adults of the annual bluegrass weevil (ABW) spring generation have started to emerge in significant numbers over the last few days at Rutgers Hortfarm 2 in New Brunswick and at golf courses in North Jersey. Peak densities of new ABW adults should occur throughout the central and northern New Jersey and the NY metropolitan area over the next 1-2 weeks.

These spring-generation adults mate and will start laying eggs quickly. The resulting second generation is present predominantly as large larvae around late July-early August, when additional damage — usually less severe than spring damage — may occur. The second generation pupates in August and starts emerging as adults around mid-August.

Areas where significant adult densities are observed (directly, in clippings, with soap irritant, or by vacuum sampling) in late June-early July may need to be treated. However, overuse of insecticides, particularly of pyrethroids, is likely to lead to the development of pesticide-resistant ABW populations. To avoid this highly undesirable scenario insecticides should be applied only where and when necessary and pyrethroids should be used no more than once per year. [Read more…]

By Jim Murphy

Back on May 24, I posted about my observation of crabgrass emerging in areas that had very thin turf cover and very high levels of crabgrass seed in the soil. Crabgrass is now emerging from areas with healthier turf and good density (and has not received a preemergence herbicide application). Recent and forecast rains are likely to intensify crabgrass pressure over the coming days and weeks. It is time to start scouting areas for breakthrough of crabgrass, if this is a concern. Postemergence control options were summarized in my earlier post. Click here to access Dr. Stephen Hart’s fact sheet on crabgrass and goosegrass control.

You can see our herbicide evaluation trials (synthetic and organic products) during the Rutgers Turfgrass Research Field Days on 30 and 31 July 2013 at Hort Farm No. 2 in North Brunswick NJ. Register online for one or both days; click here to register.

Source: Read More on the Rutgers Turf Blog

By Jim Murphy

Unfortunately, we had annual bluegrass invasion into the 2011 Kentucky Bluegrass Trial, sponsored by the National Turfgrass Evaluation Program (NTEP). As a result, we are trying a relatively new herbicide,amicarbazone, in combination with paclobutrazol on the borders of the 2011 trial.

Light-colored patches of grass are annual bluegrass plants in Kentucky bluegrass border of the 2011 NTEP trial at Hort Farm No. 2 in North Brunswick NJ.

The tank mix we used was 2.0 oz per acre of amicarbazone + 1 pint per acre of paclobutrazol. Injury to the annual bluegrass was highly visible around 2 weeks after the initial application (left side of this image). Annual bluegrass on the right-side of the image was not treated and, as result, no injury.

Kentucky bluegrass is more sensitive to amicarbazone than other lawn grasses like tall fescue and perennial ryegrass. The maximum recommended rate of amicarbazone on Kentucky bluegrass is 2.0 oz per acre applied no more than twice in the spring at temperatures less than 85° F.

On the left is injury to Kentucky bluegrass from an intentional double-treatment (4.0 oz per acre) with amicarbazone. The yellowing of Kentucky bluegrass on the right side of the image is due to amicarbazone applied at the 2.0 oz per acre, the maximum recommended rate. Image taken about 2 weeks after application.

Read More on the Rutgers Turf Blog

By Jim Murphy

Anthracnose disease was active as early as April 16 this year and has intensified in recent weeks on our low N fertilization plots.

One of our experiments has the objective of determining whether anthracnose can be managed with curative sprays if the turf is maintained under best management practices (BMPs).  The disease management goal is to keep disease severity below 10%, a subtle level that does not impact visual quality or playability (ball roll).

Our curative fungicide program included one spray just before the expected onset of disease followed by subsequent curative applications of fungicides. Curative sprays were applied once disease symptoms reach 5% with repeated applications occurring no sooner than 7-days and only if disease was active (severity increase). Our study focused on the practices of mowing height (0.090 vs. 0.125 inch) and N fertility (2.05 vs. 4.10 lbs. per 1,000 sq. ft.).

We were pleased to find that turf managed with BMPs required fewer fungicides but we were very surprised by how much. Annual bluegrass turf maintained under BMPs required 60-78% fewer fungicide sprays than turf maintained with one or two non-BMPs.

In this year’s trial, we have already applied several fungicide applications this year on plots receiving the lower N fertility regime.

You can see these plots for yourself at this year’s Rutgers Fine Turf Research Field Day at Hort Farm No. 2 in North Brunswick NJ on 30 July 2013. Click here to register. Hope to see you in July!

Source: Read More on the Rutgers Turf Blog