An Ounce of Prevention is Worth a Pound of Cure
|By Igin Staff|
Suppose you had the opportunity to create a perfect landscape. The grass would always be green, the color beds would always look neat and the trees would stand guard ? tall, straight, and
sturdy. It would be a disease-free landscape. No unsightly chewings on the color beds, no spots of insect damage on the turf, and the trees would have a canopy that would have beautiful leaves and
provide the shade and aesthetic beauty that we always desire.
If you could provide this type of service to your clients, I would imagine they would be delighted; more importantly, they would be willing to pay a little more. Being competitive does not always mean being the lowest bidder.
Although I can?t tell you that the grass will always be insect free (or for that matter, the color beds), I can tell you that once you detect the damage, you can treat that area for containment.
But suppose I tell you that on trees, ash trees in particular, you can apply a treatment and prevent the damage from occurring? That would be a major feat. Well it is, and it?s here.
Ash trees in particular make for excellent trees in the landscape. The white ash is known for its beautiful purplish fall color and the green ash for its golden fall color. They grow faster than oaks, are readily available, and are usually less expensive. However, in recent years the emerald ash borer (EAB) has taken to devastating these trees. It seems the EAB enjoys the ash trees as much as we do, but for dietary purposes.
Enter the enemy
Believed to have been a stowaway from Asia, possibly hidden in a wooden crate, a new creature was introduced to the United States in early summer, 2002. Eight million ash trees have since died, and despite officials? best efforts, the EAB has yet to slow down.
Trees do wonders in the world of landscaping, for obvious reasons. They are practical, providing oxygen and shade. They are beautiful and diverse, each species providing their own montage of colors for the changing seasons. Like a fine wine, as trees age they only make the scene even more beautiful, adding a timeless facet to the landscaped canvas.
The emerald ash borer threatens all of that. All that hard work, planning, labor, and customer?s money can go to waste in a matter of a few years after this terrible insect makes a visit. Everyone loses because of this insect: the customer, nature, and you. The extent of how much could be saved with educated treatments against the emerald ash borer is enormous. What you could offer to your clients in the form of preventative measures and treatments are not only profits for the taking, but environmentally life saving as well.
Remember that adage, ?know your enemy?? Well, let?s talk about said enemy and some of its characteristics. As stated earlier, this bug?s name is the emerald ash borer (Agrilus planipennis) and is native to China, eastern Russia, Korea, Japan, Mongolia and Taiwan. It is believed this nasty critter first landed in Michigan. It is enjoying one heck of a tour; it has affected 13 Michigan counties, along with guest appearances in Ohio and Canada.
What about natural controls? Forget about them, they left those at home. Predators, fungi, path-ogens, and parasites that enjoyed making the borer their lunch didn?t come with EABs when they came over here, so the insect is having more fun than a 12-year-old kid locked alone in a candy store.
Confined to a diet of ash trees, the EAB belongs to a family of metallic wood-boring beetles that feasts on green, white, black, and other horticultural varieties of ash, except for mountain ash. But you?re the good guy, and as we all know, the good guy always wins. So pay more attention, because there is still more to know in the biology department of this critter.
EAB life cycle
The insect emerges from an infested tree in the middle of May, leaving ?D? shaped holes in the tree that are caused by the larvae?s flat backs and rounded bellies. As adults, they are fliers and will occasionally eat foliage. A female roughly lays about 75 eggs, usually around the trunk and on the bark of branches. The eggs hatch in a week, and from May to August, the larvae begin to burrow their way into the tree and feed in the area between the inner bark and outer ring of wood. This burrowing is what causes the fatal damage to the tree, as the tunnels created by the larvae disrupt the transfer of water and nutrients. This larval stage lasts until about October. As the larvae continue burrowing and therefore eating, the branches begin to die. The canopy declines and decreases until the tree is finally dead. After spending the winter inside the declining ash tree, the larvae pupate and emerge from the tree as adults. The cycle then begins again.
So what, you may be asking right now. How does this stuff apply to me? I just simply want to destroy these deadly pests. Well, the life cycle of this annoying pest is important to consider for treatment of an infested tree. There are certain factors to think about when considering a method of eradicating this borer.
For starters, the burrowing that the larva does such a good job of, disrupting the transfer of water and nutrients, is also the same thing that makes saving an infected tree difficult. Not only does that burrowing stop water, it also hinders the transfer of internal insecticides. So the proper timing ? when during the course of a year the borer is at its flying stage and when the larvae will start boring ? is important to understanding when a specific method of treatment should be used. This is essential to successfully killing the insect.
Enter the silver lining in the form of tested treatments that
are proving formidable weapons against these beauty destroying and financially devastating pests. As proven by a recent study conducted by the Department of Entomology at Michigan State University, there are treatments out there that have worked wonders in their studies, and therefore, can be used to work wonders for your clients.
The WMBD, or Weapons of Mass Borer Destruction, are more than available. You don?t even need United Nations approval either.
This is a good thing. When you have a tree that takes many years to grow and a creature that takes only a few years to kill it, common sense dictates that the borer is more than worth considering when treating your clients? trees. Also, unlike the Asian Longhorned Beetle (ALB), the EAB is not under a treatment quarantine. This means that the licensed landscaper or applicator has an opportunity to expand his or her business, which is prohibited under the USDA quarantine of ALB. And hey, making a buck or two at the same time that you?re being appreciated for conscientiousness isn?t a bad thing either.
In January of 2003, Michigan State University conducted a study of the different treatments and chemicals used to treat trees infested with low to moderate EAB densities. The findings show that the best chemical control proved to be imidacloprid. The report states that this chemical has relatively low toxicity to humans, birds, and certain groups of non-target insects. Made by Bayer, this chemical is the active ingredient in Imicide, which is manufactured by J.J. Mauget for use in trunk injections; also available is Pointer, which is marketed by ArborSystems, and Merit, by Bayer, which is used as a soil drench.
When to throw in the towel
According to Deborah McCullough, Ph.D, and David Smitley, Ph.D, in the Department of Entomology of Michigan State University, ?trees with more than 20% canopy die-back usually have extensive tunneling injury that will be difficult to overcome.? That does not leave a very accommodating margin of error, if heavy infestation is already present. Odds are you are probably going to have to down and remove the tree while observing local quarantine procedures. Anything else will most likely be a waste of time, money, and chemicals.
Therefore, the best solution is obvious. Try to recall another popular adage, one that some motherly figure probably ground into your head while yelling at you to put a coat on before you went outside: ?An ounce of prevention is worth a pound of cure.? According to experts, following this rule of thumb gives you the best odds of protecting against EAB.
Know your options
But how do you do that? Well, there are a few methods of application from which to choose, including trunk injections, sprays and soil treatments. Each has its advantages and disadvantages; some with more advantages than others. It is generally recommended that more than one method of applying the insecticide is used. Also, depending on the time of year, different treatments may work better.
Remember that EAB biology lesson earlier? Hope you do, because this is where it applies to deciding how to defend against this bug. The boring stuff about the life cycle becomes applicable. For instance, between June and July, spraying trees with insecticide will be far more effective, since that is when the EAB are adults and could fly to other trees. Spraying between August and October, when the borer is, well, currently boring into the tree, and safe from topical chemicals, isn?t going to be as effective. There are risks with the spray, as applying it near open water may be prohibited due to potential drift and may be toxic to beneficial insects you don?t want to destroy. Personal exposure to the chemicals, which would be likely if near homes, could also be problematic.
Another measure is a soil drench or injection; the best time to apply this treatment would be in April and May. These treatments will take four to eight weeks for the roots to absorb the chemicals and move up the tree. This will make the tree?s tissue poisonous for the borers in time for when they begin to chew into the wood, which is between July and August. Soil treatments are good, since they don?t involve any additional injury to the tree, and drift associated with sprays are not a concern. They also have minimal effect on non-target insects. However, good soil moisture is necessary for chemical absorption and if the tree is already deeply wounded by EAB, the treatment will probably not be effective. Also, this method is highly discouraged by some professionals due to the potential of polluting groundwater. Some counties, like Nassau and Suffolk in New York, will not even allow soil treatments because of this.
Trunk injections are similar to the soil injections in terms of minimal exposure hazards. You have a better window of margin when it comes to proper timing with injections, with application being necessary between two to four weeks before EAB infestation, as opposed to the soil treatment?s four to eight. This is the best preventative measure against EAB, but if trees have sustained heavy damage in previous years or are already unhealthy, translocation of insecticide will be hindered.
If you miss the time frame for using imidicloprid, and the EAB is in full bloom, the knock-out punch is Injecticide-B, another J.J. Mauget product for trunk injections, utilizing Bidrin (dicrotophos). In tests by Michigan State University, Bidrin was found to be highly effective and toxic for adult EAB control for more than four weeks after injection.
Today, the EAB is densely populated in select counties in Michigan, Ohio, and Windsor, Ontario, Canada. Landscape contractors and arborists in these counties should be especially diligent in adhering to local laws instructing proper destruction protocol, and should consider EAB prevention measures for client?s trees before the trees are actually infested. Here?s a very real and tangible opportunity for all to benefit from your efforts in curtailing this insect. Currently, it is an isolated problem, but this EAB match found one heck of a tinderbox billions of ash trees grow in North America.