Watch for three non-native insects which can cause widespread damage.
By Lynne Galluzo
When we lived on a quarter acre we got our exercise by walking the network of paths in and around Virginia Run. One evening we went “off road,” following one path leading to another, and discovered something we had never seen before. It was a huge expanse of yard that was only grass and large trees. No shrubs, no flowers, no mulch circles—just tall trees to contrast a beautiful green lawn. It was a surprise and sort of magical.
When we moved to our current 10 acres, there was an area by the creek where we emulated the same effect. This location contained a few shrubs, some grass, and lots of very tall, straight trees. We cleaned out the undergrowth, thinned out the young, skinny trees and created our own “park.” We have called that area The Park ever since. We incorporated a bench swing facing the creek, there is stunning green grass, and tall trees provide shade. Ash trees make up the majority of the trees in The Park.
We had heard about the emerald ash borer, and we maintained hope that our ash trees, their favorite target, would escape this deadly bug. Unfortunately, last year we saw our beautiful trees were dying.
Emerald ash borer
When a tree is infested, the canopy of leaves die first, and then the bark falls off in chunks. The adult beetles, metallic green and about a half-inch long, eat the leaves, but this is not what damages the tree. The female beetles lay their eggs in the bark crevices. The eggs hatch in two weeks, and the young borers chew through the outer bark, where they spend up to two years eating the inner bark before they emerge as adults. The inner bark transports water and nutrients through the tree, and once this process is effected, the tree dies.
The emerald ash borer arrived in the United States in wood packing material from Asia. It was first detected in southeastern Michigan, near Detroit, in the summer of 2002. Since then it has spread to 29 states and Canada. There are 8.7 billion ash trees in North America and every one of them is susceptible to this bug.
This infestation has killed millions of trees and has cost millions of dollars to municipalities, property owners, nursery owners, golf courses, and the forest product industry. There are dead ash trees by homes and roads which will need to be removed before they fall and cause damage. The dead trees in wooded areas upset the ecological balance, allow invasive plants to flourish, and create more fire tinder.
There are predators of this bug, as well as resistant species of ash trees, but not located in our region of the world. Incredible efforts have been spent on monitoring the borer and developing insecticides and biological controls. This is a reactive response instead of proactive. And it might be too late, as it is for The Park on our property.
Because “misery loves company,” let me look at another uninvited and unwelcome guest—Japanese beetles. There has been a story told which states a scientist brought seven beetles from Japan to study and these insects escaped, but this is not true. History reveals something a bit closer to fact; the beetles arrived in a shipment of iris bulbs sometime before 1912, which is when inspections of cargo entering the United States began. These pesky bugs showed up in a nursery in Riverton, New Jersey in 1916. They are not destructive in Japan because they are controlled by natural predators, but here they are having a grand time, again at huge expense.
They enjoy eating roses, grapes, hops, cannas, crepe myrtles, rose of Sharon, birch trees, linden trees, cherry trees, and many more. It is a frighteningly long list. They eat all of the soft material in a leaf, leaving skeletal remains. They also dine on fruit and flowers.
Japanese beetles have four life stages: egg, larva, pupa, and adult. They spend most of their time in our soil as larvae—those white, curved grubs that I have learned to squish with my fingers whenever I find them. When the weather warms they emerge as hungry adults. I have seen one as early as May 28 but they are heaviest for 30 to 45 days in the summer. I am writing this at the end of June and I have been doing “beetle patrol” for over a week.
An adult female can lay as many as 60 eggs, so anything we can do to stop the spread of the beetles is a good thing. The Japanese beetle traps that are widely sold are based on pheromone lure. Unfortunately, studies have found that the devices are more lure than a trap, and having one, even far away from your targeted plants, can attract more beetles than it will kill. Milky spore, injected into the ground at regular intervals, is very effective at killing grubs, but it takes almost five years to have a positive impact and needs to be used by whole neighborhoods.
There are natural repellents like catnip, garlic, and tansy, but how many of these do we need to plant to keep them off of our roses? Because beetles have been around since 1912, there are lots of home remedies, including fermented fruit cocktail. Seriously, you can look it up. Unfortunately, some toxic powders and sprays are also toxic to honeybees. For this reason I will not use them, but continue to tour my garden in the morning and evening when beetles are slower. I will continue to drop them into a can of soapy water.
Asian longhorned beetle
I had a young man from County Extension Office come out to inspect our trees to confirm the emerald ash borer as the culprit killing my trees. He also told me about a new threat—the Asian longhorned beetle. It arrived in the United States in 1996 from China, again in packing material. While the main target of this beetle is maple trees—horrors—they also enjoy horse chestnuts, poplars, willows, elms (are there any left?), birch, mulberries, black locusts and others, including the ash.
These beetles were first discovered in Brooklyn, Amityville (do they need another horror?), and Chicago—all cities near ports. Since then they have also been seen in Massachusetts, Illinois, Ohio, and Ontario. Because we have learned from past experiences with Japanese beetles and emerald ash borers, detection was early. Existing beetles have been eradicated and authorities are on high alert for this pest.
I believe that if you read my articles, you share my enjoyment and enthusiasm for the wonder and beauty of the great outdoors. The best we can do is help it, and not hurt it. If you can kill a harmful bug by smashing it or drowning it, that is so much better than spraying with chemicals which may be lethal to many beneficial insects.