Because we have so many ash trees in our region, I am turning this week's Extension Lines over to Dr. Jeff Iles, Iowa State University Horticulture Department Chair, to share an update on living with the Emerald Ash Borer (EAB).
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 homeowner or perhaps as a community tree volunteer? Do you put the blinders on and pretend the insect will never find your yard or community? 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 landscape. But what about the thousands of ash that line your streets, shade the local park, or otherwise look pretty good and contribute to the overall beauty and ambiance of your community? 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 own household or community has miraculously survived the recent economic downturn without a scratch, you simply can't afford to protect every ash tree in sight. 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...when the insect is found in Iowa, or even better, when it is found in your county.
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)
Acer miyabei 'Morton' (State Street® miyabe maple)
Acer saccharum 'Bailsta' (Fall Fiesta™ sugar maple)
Ginkgo biloba -- 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)
Ulmus × 'Morton Glossy' (Triumph™ elm)
To read more about the Emerald Ash Borer threat, visit http://www.extension.iastate.edu/PME/Eme...