July 2006

In the Crosshairs
By Paul Diegnau, CGCS
Keller Golf Course
Maplewood, Minnesota


The new patch in town and EAB revisited

Emerald Ash Borer continues its unstoppable move westward. On June 13 of this year, EAB was found in a suburb of Chicago, Illinois. On July 13, a second infestation was found north of Chicago. Illinois is now the fifth state to succumb to the advance of this insect. The other infested states include Michigan in 2002, Ohio in 2003, Maryland in 2003, and Indiana in 2004. Currently there are approximately 40,000 square miles of infested land in the U.S. and Ontario, Canada. Potential costs of EAB are estimated to be in the hundreds of billions of dollars if this exotic pest continues to spread across the U.S.

EAB Adult Beetle

Obviously this little borer is a big deal, especially with ash species comprising a significant portion of the urban landscape in Minnesota. Most experts, using currently available information, believe this pest will not be stopped. The biggest problem we face on the EAB front is keeping infested firewood within quarantined areas. The female EAB can only fly about one-half mile on her dispersal flight so the natural spread of this pest is relatively slow. Man, on the other hand, can move infested firewood great distances in a short amount of time. The key to slowing the spread of EAB is containing the movement of firewood.

Larval channels from EAB

Raising public awareness can also be effective in slowing the spread. Current thinking suggests that EAB was in the Detroit, Michigan area for possibly ten years prior to discovery. As some "experts" have speculated, EAB may already be in Minnesota. Do what you can to educate and inform the people you come in contact with. An informed public brings many eyes into the outdoor world. The Asian Long-horned beetle outbreak that occurred in the Chicago area several years ago was contained with the assistance of informed city residents. Press conferences, beetle hotlines, and a massive public education campaign did the trick.
D-shaped exit hole of EAB adult

For my final point let me quote Mark Stennes, plant pathologist and ISA Board Certified Master Arborist with S&S Tree Service. At a recent MTGF board meeting, Mark made an emphatic plea to the board members to "STOP PLANTING ASH TREES!!!" His position is simple…EAB will eventually get to Minnesota and the impact this insect will have on our ash trees will rival, if not exceed, what Dutch Elm Disease did to elm trees in the 1970's. Plant other species on your golf course and avoid the eventual removal costs, replacement costs, and heartache. Mark highly recommends 'Princeton' Elm as an alternative. If Mark's comments didn't get your attention, here are some comments off of "Turfnet" from several Michigan golf course superintendents who are currently in the thick of things:
"It has devastated Michigan and you can count on every one of your Ash trees getting infected. It's worse than DED for sure."
"I watched every Ash tree at my golf club get infected and die in less than 2 years. Don't buy the hype that insecticides will work ... they don't."
" The park system I now work for has taken down nearly 9000 ash trees to date in the thirteen parks that we have. It is a destructive insect that kills an untreated tree quite rapidly."

Waitea What?

This summer, a new turfgrass disease has been showing up all across the U.S. It made itself known here in the great state of Minnesota in June. I believe Keller GC experienced an outbreak in late June (see photo) and I know at least five other golf courses dealt with it, several having its identification confirmed by a pathology lab. It is a relative of the Rhizoctonia family and goes by the common name of Waitea Patch. The scientific name of this pathogen is, depending on whom you talk to, Waitea circinata var. zeae, Rhizoctonia circinata var. zeae, or simply Rhizoctonia zeae. The rings are between four inches and two to three feet in diameter and the centers of the patches are usually green and healthy. The primary turfgrass affected is Poa annua but it can be found on creeping bentgrass. The symptoms can resemble yellow patch (Rhizoctonia cerealis) but this pathogen occurs under much warmer temperatures. It may also be mistaken for fairy ring but diagnostic results from across the country are not finding fairy ring fungi.

Waitea Patch?

The good news is that standard Rhizoctonia fungicide treatments are effective in controlling this disease. Banner MAXX, Medallion, Endorse, and Heritage showed the best control in trials conducted at Torrey Pines in California.

(Editor’s Note: For additional information, check out: www.paceturf.org (Pace Turfgrass Research Institute) http://hcs.osu.edu/sk/

- Paul Diegnau
Certified Golf Course Superintendent
Keller Golf Course, Maplewood