By Jim Murphy

I have seen as much disease damage on turf this summer as any year since I began living and working in New Jersey. The weather has been ideal for summer patch and brown patch diseases. Summer patch disease is caused by a root infecting pathogen, Magnaporthe poae. I have observed more damage on hard fescue turf than Kentucky bluegrass. This is likely due to the fact that many people are growing varieties of Kentucky bluegrass with better tolerance of the disease than was the case 20 or more years ago.

There are some cultural techniques that can reduce the severity of summer patch disease including:

1. Fertilize at no more than 1 lbs. of N per 1,000 sq. ft. per application and 2 lbs. annually)
2. Use an acidifying N source (for example, ammonium sulfate)
3. Reduce soil compaction (aerify)
4. Maintain a slightly acidic soil pH (around 6.0); do NOT lime until pH reaches mid to low 5′s and do NOT attempt to increase the soil pH much above 6.0
5. Use seed mixtures (rather than blends) that include tolerant species when seeding hard fescue or Kentucky bluegrass as a major component of the turf. Hard fescue and Kentucky bluegrass (depends on the variety) are sensitive to summer patch.
6. Seed with tolerant species which includes tall fescues, perennial ryegrass, and Chewings fescue. Chewings fescue can be damaged by summer patch disease but it is more tolerant than hard fescue as you can see in the image below.

Links below open PowerPoints on summer patch disease prepared by Dr. Bruce Clarke.

Getting to the Root of the Problem; Biology and Management of Patch Diseases

BMPs for the Control of Summer Patch on Annual Bluegrass Turf

Source: Read More on the Rutgers Turf Blog

By Jim Murphy

We receive requests for information on “organic” alternatives to glyphosate (e.g., Roundup), especially for “trim” sprays on paved areas, sidewalks, skin surfaces on ball fields, etc.

The research on organic non-selective herbicides that are being marketed as replacements to glyphosate (for example, Roundup) is growing but it is much more limited that what you can find on more conventional herbicides; however, we have been evaluating some products. Our results indicate that these alternative products are short term “burn-down” products that have the ability to kill small immature plants. On the other hand, large perennial plants, while looking sick to dead soon after being spray, start to re-grow a week or so after being sprayed.

Therefore, we only recommend these alternative products for “trimming” applications on immature (very young, small plants vegetation. These products will be very disappointing if you practice an infrequent “trim” spray schedule (once or twice a year) that is treating a mixture of young and old plants. The immature plants are likely to die but you will find that the large perennial plants will survive and continue to grow once the product’s burn-down effect wears off. [Read more…]

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.

Read More on the Rutgers Turf Blog