In Defense of Nature

 Emerald Ash Borer—Save the Tree, Endanger the Ecosystem

A purple-box survey program was carried out by the U.S. Department of Agriculture to detect the spread of Emerald Ash Borers throughout the country. Coated with an “extremely sticky” glue, the numerous traps each caught and killed a large variety of insects (including butterflies) that were viewed as collateral damage by authorities. As very little could be done to halt the spread of EAB, the purple boxes simply served to deplete already-dwindling insect populations.

ALL TEXT AND PHOTOS © Marlene A. Condon

 

Almost 20 years ago, I attended a Virginia Outdoor Writers Association meeting that was held at Mountain Lake near Virginia Tech [VT]. A VT entomologist led us on a walk around the lake. He spoke about the systemic pesticide injections they were using to try to save the hemlock trees from the overly populous nonnative Hemlock Woolly Adelgid (Adelges tsugae) feeding on them.

 

A systemic pesticide is one in which the active chemical ingredients are water soluble so that the pesticide is absorbed by a plant and then circulates throughout the plant’s system. It’s akin to the chemotherapy used to treat cancer patients, except that instead of killing cells within the organism itself, as happens when a person is treated, the chemical kills any critter feeding on any part of the poisonous tree.

 

Therefore, I asked the entomologist if he wasn’t concerned about this effect on nontarget species (i.e., animals other than the adelgid). He answered that he’d never given it any thought.

 

As the saying goes, most folks can’t see the forest for the trees. They are so concerned about having to act to save trees that they lose sight of the bigger picture: the effects of their pesticide usage upon the ecosystem. The adelgid/hemlock scenario is now being played out with the Emerald Ash Borer [EAB].

 

Scientists and environmentalists alike argue that we cannot afford to lose our native trees because they support native insects. But what is the ecological value of using poison to keep alive an ash tree that will attract such critters as the Tiger Swallowtail (the state insect/butterfly of five states, including Virginia where I live) and then kill its caterpillars, among a multitude of other leaf-eating insects?

 

The pesticide Emamectin, recommended for EAB control, is widely used to eradicate “lepidopterous pests”—the caterpillars of moths and butterflies. It doesn’t discriminate between the larvae people want to get rid of and the ones they don’t. Imidiclopid can be used instead, but this pesticide has been implicated in the deaths of honey bees.

 

I’ve read that “Only about two-thirds of a teaspoon of active ingredient is used to treat the entire tree.” This statement suggests that the quantity of insecticide used is insignificant, but the quantity isn’t important—the effect is.

 

A catastrophic result of treating trees with an injected pesticide is that those trees become perpetual killing agents. In this time of increased environmental consciousness, most folks understand that the wanton extermination of non-targeted species is unsound.

 

You might think these animals are doomed to die anyway if the ash trees aren’t rescued, but that’s not necessarily true. Most of these insects are generalists that can feed upon a variety of plant species, but they won’t be able to move along to other plants if they are dispatched by the pesticide in your trees.

 

People shouldn’t be so willing to accept the poisoning of the creatures upon which the functioning of our environment depends. Rather than providing cost-share programs that monetarily assist folks to exterminate numerous species of arthropods, government should have spent its (our) money more wisely by paying citizens to collect ash seeds that could have been preserved to be planted after borer populations have plummeted—as they will.

 

As soon as large ash trees are greatly reduced in number, most of the borers will starve for lack of a food source. Meanwhile, a natural buildup of predator populations will have taken place to keep remaining borer populations in check.

 

I’ve lived at my nature-friendly and pesticide-free property for over 35 years, and native predators have always kept the numbers of Gypsy Moth (Lymantria dispar) and Japanese Beetle (Popillia japonica) limited to such a low level that I rarely see them. They are not at all problematic for my plants.

 

It should be noted that poisoning the Earth with chemicals has never solved nonnative-insect problems. Despite spending many millions of taxpayer dollars on pesticides, we still have Gypsy Moths (in the country since 1869) and Japanese Beetles (here since 1916).

 

The course of action to take cannot be based solely upon hysteria that makes people think, “We’ve got to do something (anything!).” Mother Nature can handle this situation far better than humans because the natural system of checks and balances works—far more sensibly and safely than our misguided efforts with pesticides.

 

NATURE ADVICE:

 

You might want to reconsider obtaining free leaves from friends and local government-run programs. Given people’s propensity these days to employ pesticides, you may be adding poisons to your garden. Yikes!