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Emerald Isle

Update (7/12/2013)

Hunting Billbugs Hit MO

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**Diagnostic Lab Closed Temporarily**

I will be out of the country next week.  If you have a diagnostic need, either send samples later next next week (Wednesday or Thursday) or on Monday, 7/22.   I will have limited access to email, so let me know if you have a sample on the way via email. 


Missouri is heating up and drying out.

Normal or slightly above normal now feels a little hot, as temperatures spiked to begin the week.  The lower 60s and high 80’s we are experiencing now and the lack of humidity certainly feel nice, and I would love to dial up this for a certain MU field day event in late July.  Forecasted temperatures look to be at or slightly above average for next week, with a return to lows in the mid 70s and highs in the lower 90s for the region.      

We are drying out from the 7” + surplus we had up to June 30th, but have not gotten on the radar of the U.S. drought monitor yet (  This is not the case, however, for our neighbors to the west, as Kansas is experiencing significant drought, particularly in the western part of the state.   Just driving around, however, it is evident that tall fescue lawns are starting to brown into dormancy, and homeowners need to commit to supplemental irrigation or simply leave it alone. 

Quick Hits

  • Numerous diagnoses on golf putting greens included basal rot anthracnose of creeping bentgrass near southeast MO, abrasion of putting greens collars, high organic matter causing anaerobic root decline, and combination of herbicide injury + take all patch.  Tall fescue issues included heat stress & dormancy, and brown patch.  This pales in comparison to the current outbreak of hunting billbug which is noted below. 

Hunting Billbug Outbreaks Hit MO Zoysia Hard

Billbugs are a considerable problem now for zoysiagrass in MO.

Hunting billbug issues on zoysia are by far the biggest story of the last few days, and therefore bump everything else aside.  Damage is now appearing on golf courses and our turf farm in Columbia and, as of a confirmed reports an hour ago, also in both St. Louis and in Kansas City

Dollar spot damage on zoysia can mimic early symptoms of billbug damage.

Early symptoms of billbug damage appear as 3-6” diameter brown areas that closely resemble dollar spot and which may be going misdiagnosed now (see photos of dollar spot of zoysia above).  We typically see dollar spot in zoysia in the fall and spring when the turf is coming out of dormancy and a nitrogen application has not been made.  If you see these spots, dig into the soil profile and look for 1) hollowed out stems, 2) frass, and 3) the most tell-tale sign: a small pinkie-sized legless grub about ¼” long residing about 1” below the soil surface.  These larvae started out inside the zoysiagrass plant as an egg laid a few weeks ago.  That larva you find has hatched and ate its way through the plant stem, popped out a stolon or rhizome, and is continuing to eat the roots.  Meanwhile the adults are roaming around, taking a nibble, and continuing to lay eggs. 

Aside from the newness of this pest and our unfamiliarity with it, a considerable problem is that ‘Meyer’ zoysia accounts for 99.99% of the zoysia acreage in this region… and this cultivar just happens to be most appetizing and susceptible to hunting billbug damage.     

Upon initial diagnosis of the hunting billbug problem in 2011 and 2012, damage was thought to be limited to the St. Louis area and mainly only on lower maintained zoysia lawns.  At the course in Columbia, the problem was detected last year in just a few areas of the course and only on one side, but the damage has now spread to the entire course.  Now it seems the critter has traversed I-70 (bus?) and is now present in Kansas City.  It is unclear why damage is so widespread and evident this year instead of 2012, unless damage was simply undetected last year due to the drought conditions.

At sites with a history of damage, (which there may be more of in a few weeks) a preventive insecticide application of bifenthrin (Talstar), deltamethrin (Deltagard), lambda-cyhalothrin(Scimitar or Battle), or imidacloprid (Merit) for control of adults should be made in April or early May in this region.  For these preventive applications, the entire fairway may not need to be sprayed, and instead a loop around the outside of the fairway edge and into the intermediate rough may be enough to get the emerging adults.  For larval control, clothianidin (Arena) and thiamethoxam (Meridian) are most effective.  NOW, however, for curative control we are looking at attempting to control both adults and larvae.  This will require an application of either thiamethoxam + a pyrethroid or a combination product like clothianidin + bifenthrin (Aloft).  These applications should be watered in with 1/8-1/4” of irrigation to get the insecticide to the billbug grubs.

Dr. Brad Fresenburg and I are currently evaluating Acelepryn and other treatments at the MU turf farm, and dinotefuran (Zylam) at the off-farm site in Columbia.  Dr. Fresenburg will be discussing hunting billbugs and control options during his talk at field day, and we will be able to show you what damage symptoms look like since it is well established at the farm.

New Handbook of Turfgrass Insects

Many thanks to Dr. Rick Brandenburg, Dr. Callie Freeman, and doctoral student Diane Silcox from North Carolina State University with their help in understanding the biology and control of this pest.  Dr. Rick Brandenburg joined us last year to present at the Missouri Green Industry Conference on hunting billbug control.  Dr. Callie Freeman is the current owner of Parker Biolabs LLC and completed her dissertation research on this subject, while Diane Wilcox, M.S. is currently working on her PhD dissertation on developing hunting billbug controls.  Additionally Dr. Brandenburg and Dr. Freeman are the chief editors for the recent “Handbook of Turfgrass Insects – 2nd edition”, which is an invaluable resource and has a big hunting billbug right on the cover.   A bit of foreshadowing perhaps for MO...

Field Day, July 30th – Save the Date.

Attendee registration is now open for the MU Turf & Ornamental Field Day on July 30th. Vendors/exhibitors - we had a full boat last year, and many commented that it was the best bang for their field day buck during the whole season.  We will have a dedicated demonstration time before lunch (contact me for details on setup), when you can show your wares in a turf setting.  We also have several sponsorships available to support the event.

Links are below to access registration for both attendees and vendors, and the complete field day agenda. Hope to see you there. 

For the full agenda, click here.
For attendee registration, click here.
For exhibitor/vendor registration, click here.

Thanks for your support of the program.

Lee Miller
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Extension Turfgrass Pathologist
University of Missouri 

Field day talks include wetting agents, tree care, lawn care, and disease updates.