Search results

Living with the Emerald Ash Borer: by Jeff Iles

October 7, 2009

While not an “official” resident of the state of Iowa, yet, the highly destructive emerald ash borer has been found within a stone’s throw of our northeastern border. And if you’re a pessimist or perhaps a realist, you might be convinced the insect is already here, but has managed to escape detection. After all, it’s not the easiest of pests to locate. Just ask our colleagues in southeastern Michigan. Either way, it’s probably a safe bet that very soon EAB will be with us, and its impact will be dramatic and widespread.

So, what do we do? What do you do as a golf course superintendent? Do you put the blinders on and pretend the insect will never find your course? Do you adopt a scorched earth policy and “fell” every green, white, black, and blue ash on your property just so you don’t have to worry about EAB in the future? Move to Nebraska? My answers to these questions are no, no, and heck no!

Here’s what I would do. I’d take inventory of every ash tree under my care. Those found to be in a serious state of decline would become intimately acquainted with Mr. Chainsaw. No sense hanging on to trees that look bad and detract from the appearance of the course. But what about the thousands of ash that line your fairways, frame a green, or otherwise look pretty good and contribute to the overall beauty and ambiance of your course. Well, if it were up to me, I’d continue to prune, water, and mulch them, and…enjoy them. We all might be surprised just how long these trees are with us, even after EAB enters the state.

Notice, however, that I haven’t yet mentioned preventive insecticide treatments. And why would I? Unless your golf course has miraculously survived the recent economic downturn without a scratch, you simply can’t afford to protect every ash tree on the course. But, if you have one or several extremely old, historic, or noteworthy specimens you simply can’t afford to lose, then relying on an insecticide to protect your investment makes perfect sense.

These are trying times for golf course managers. Heck, these are trying times for most businesses in Iowa and the last thing the “green industry” needs is the loss of popular, dependable, and heretofore trouble-free tree species. But that is the hand we’ve been dealt and it’s the hand we must play. That is, unless you’d rather fold and go home? I didn’t think so.

So, let’s stop trembling in fear of this little green beast from the east and begin making a plan for the future. Of course, the plan does not include planting more ash, but look on the bright side. Ash are overrepresented in most Iowa landscapes anyway, so now’s the perfect time to diversify your tree population. Looking for some examples? Try these on for size.








Acer ×freemanii 'Sienna' (Sienna Glen® Freeman maple) (Picture Above)

Acer miyabei 'Morton' (State Street® miyabe maple)

Acer saccharum 'Bailsta' (Fall Fiesta™ sugar maple)








Ginkgo biloba (Picture Above) – choose male cultivars if you don’t want fruit litter
Gleditsia triacanthos var. inermis 'Harve' (Northern Acclaim™ honeylocust)
Gymnocladus dioicus (Kentucky coffeetree)
Platanus × acerifolia 'Morton Thornhill' (Exclamation™ London planetree)
Quercus macrocarpa (bur oak)
Quercus muehlenbergii (chinkapin oak)
Taxodium distichum (baldcypress)
Tilia americana 'Boulevard' (American linden)
Ulmus americana 'Princeton' (American elm) (Picture to right)
Ulmus × 'Morton Glossy' (Triumph™ elm)

And there are many, many more!

Jeff Iles

Department of Horticulture

Iowa State University


Japanese Beetle Activity on the Rise

July 18, 2011
Adult Japanese beetles burrowing into a golf course putting green.

The number of adult Japanese beetles has exploded the last couple of weeks. Once confined to the northeastern region of the country, this destructive insect has become a permanent part of the Midwestern landscape. This pest has continued its trek west across the country since being introduced into the U.S. from the Orient. Japanese beeltes were first reported in Iowa in 1994 and have gone on to inhabit approximately half of the counties in the state.

The Japanese beetle is one of the white grubs that includes the May and June beetle, masked chafer, green June beetle, European chafer, Asiatic garden beetle, Oriental beetle, and black turfgrass ataenius. The adult beetles can be identified by their green and bronze metallic head and shell and by the white tufts of hair that run along their abdomen. The larval stage must be identified by their raster pattern.

As with all white grubs, the Japanese Beetle larvae feed on the roots of grass plants just below the soil surface. Injury first often appears as drought that fails to respond favorably to irrigation. Each year the adult beetles emerge from the soil and begin mating and laying their eggs. This is the period we are currently experiencing. The eggs hatch in 2-3 weeks and the larvae begin feeding. Feeding can continue through the fall up until the first frost. Injury can also occur in the spring but is usually less severe due to the vigorous growth of cool-season grasses.

This particular grub species is somewhat unique in that the adult beetles also are significant pests of a wide range of ornamental plants. Japanese beetles feeding on leaf tissue leave a skeleton framework of veins following damage. Damage typically occurs at the top of the tree and works downward. Below is a picture of a Linden tree that is under attack from Japanese beetles.

Adult Japanese beetles feeding on a Linden tree.  The beetles usually start feeding at the top of the tree and work their way down.

Monitoring for white grubs can give you an indication of the severity of damage you may be able to expect. Sites with heavy beetle infestation in the summer months are likely incur grub damage during the fall months. Also, be sure to watch areas that have been damaged in the past as grubs often reinfest the same areas.

There are a number of insecticides on the market that are effective at controlling white grub species. The key to effective control is proper timing and placement of the products. Products applied preventatively or curatively are more effective against the grubs when they are small.

Regardless of the timing of the application, it is essential that the product be effectively watered in. Using nozzles that produce larger droplet sizes will help place the product further down in the canopy. Irrigation is normally recommended to help move the product down below the thatch layer and into the soil where the product will be most effective.

Based on the number of adults we are seeing we could be set for significant damage this fall. Monitoring for adult beetle activity is a great tool for those of who haven’t treated and are trying to decide what to do. The margin for error appears as if it will be quite slim as the turf will already be experience summer decline as we move through a week with high environmental stress.

Let us know what you’re seeing out there.

Marcus Jones
Assistant Scientist





August 15, 2011

Right on schedule, the billbugs are back again this year. It is late July and early August each year that I get calls to come and look at lawns that look like they are "sick". The lawn below is in Gilbert, IA. While there is some leaf spot on this site, much of the damage was caused by billbugs.

The billbugs overwinter as adults. The adult female uses its bill (feeding mouth part) to burrow into the sheath just above the crown of the grass. She then deposits an egg in the sheath where it is is safe from most insecticides. This usually takes place in late April or early May. The egg hatches in July and the larvae proceeds to eat through the crown and to emerge into the soil. (The two pictures below are commercial slides from the American Society of America slide set on turfgrass insects)

To diagnose the problem, reach down and pull up some of the dead grass. If it is bill bugs, the grass will break away at the crown. The remaining tissue will be hollowed-out at the base.

Dig down into the soil and there will be many hollowed-out stems and a saw-dust like material left behind by the feeding larvae.

In early August, there will likely be larvae present in the soil

The larvae not very big. The picture below shows one on the tip of my pocket knife.

The larvae will soon turn into pupa and then into adults. This picture from the research station shows a larvae and an immature adult together in the same location.

The first question that I usually get from the home-owner is, "should I spray in insecticide now (in August)". The answer is no. The damage is already done and the application of an insecticide after the damage has occurred is not going to help. You have to treat the adult females in the spring before they lay their eggs. Late April is the best time to treat, however, that is difficult because they is no apparent damage at that time of year. You are also unlikely to see many adults at the that time of year.

There are systemic insecticides that could potentially be used when the larvae are in the sheath. The problem with that is that you do not see the damage before it is too late to treat.

This is a difficult pest to deal with because of these complex timing issues. If you have had a bad outbreak this year, it would be wise to invest in an insecticide application in the spring. Lawn care companies can do this, or the home-owner can do it themselves. Look for a insecticide that lists billbugs on the label. The critical thing is timing. If you apply after the eggs have been laid, you are wasting your time and money.