Natural Predators and an Emerald Prey

Woodpecker-Emerald Ash Borer

In Missouri’s natural rural forest stands, ash trees only comprise about 3% of total trees. This tree makes up a greater percentage of urban trees – 14% for trees lining residential streets up to 21% in urban parks. Visitors to the state’s parks are reminded not to bring firewood into the state from other states when camping out here and to burn whatever they obtain locally and not take it out of state when they leave. These measures act like a type of quarantine to reduce the likelihood of the insect’s arrival into any state employing similar measures.

Tiny Emerald Ash Borers (they are only 1/2″ long or about the diameter of a penny) have killed millions of ash trees since they were discovered in Michigan in 2002. The beetles in their larval form disrupt the flow of nutrients beneath the bark. Over time, they kill the tree. I believe I first became aware about the threat at our Missouri State Fair in 2012. We encourage and support a high degree of diversity for tree planting in our forest as a hedge against any potential insect infestation. In July 2008, a small Emerald Ash Borer infestation was discovered at a Wappapello Lake campground. That discovery put the potential threat in a nearby county to our own forest. Since then, the beetle has been detected in several other areas in the state.

Because the insect is a serious problem in states where it has been identified, concerned citizens and officials have looked for all the possible methods they might employ to eradicate the Emerald Ash Borer that is killing ash trees. Enter natural enemies of the Emerald Ash Borers. These include predaceous and parasitic insects and insect-pathogenic fungi. With the help of bird-watchers, researchers used information from Cornell University’s Project FeederWatch (for which my late mother in law was a long-time volunteer) and the US Forest Service to identify that the Red-bellied, Hairy and Downy Woodpeckers and the White-breasted Nuthatch populations grew in areas of known Emerald Ash Borer infestations. This was not an impact caused by birds migrating into the area but a result of local birds flourishing and successfully rearing families because they had happily discovered an abundant new food source. Fortunately, BOTH bird species are natives here in our Missouri forest and that is reassuring for our own ability to come through the latest threat with our forest still in a good condition.

According to Walter D Koenig from Cornell’s Lab of Ornithology, the birds “can depredate quite a surprisingly high percentage of Emerald Ash Borer larvae in some forests” but that “It’s unlikely that this would be enough to stop the invasion, but it could certainly slow it down, at least in some areas.” We should not discount the tenacity of the most predaceous species on our planet, human beings, to continue to look for every way possible to turn back the tide of the latest invasive species to drawn our concern.

The arthropod predators of insects and mites include beetles, true bugs, lacewings, flies, midges, spiders, wasps, and predatory mites. Insect predators can be found throughout plants, including the parts below ground, as well as in nearby shrubs and trees. Some predators are specialized in their choice of prey, others are generalists. Some are extremely useful natural enemies of insect pests. Unfortunately, some prey on other beneficial insects as well as pests. Insect predators can be found in almost all agricultural and natural habitats. Each group may have a different life cycle and habits. Although the life history of some common predators is well studied, information on the biology and relative importance of many predatory species is lacking.

While research has found that commercial chemicals can be effective in controlling emerald ash borer infestations, “you just can’t afford to do that in the woods,” said Andrea Diss-Torrance, a forest entomologist with the Wisconsin Department of Natural Resources. And some of us (this blog’s author and her husband definitely included !!) PREFER NOT to use chemicals on our land.

Chinese Stingless Wasp ~ photo credit  U.S. Dept of Agriculture

Chinese Stingless Wasp
~ photo credit
U.S. Dept of Agriculture

Two kinds of wasps are being used that will insert their egg-laying appendage through the bark and lay eggs in tunnels on, or in, emerald ash borer larvae. Once the eggs become larvae, they will eat the larvae of the beetle, Diss-Torrance said. Another species of wasps released at a different point in the seasonal cycle lay their eggs on or inside the eggs of the emerald ash borers when they are laying their eggs on the bark of ash trees. Once the larvae develop, they will eat emerald ash borer eggs.

The process will be invisible. “They are very tiny, and a lot of their work will be done inside or on the bark of a tree,” said Diss-Torrance. Entomologist Ken Raffa of the University of Wisconsin-Madison said that “these wasps have undergone intense scrutiny by the USDA to safeguard harm against native species.”

Sometimes, biological controls have interesting consequences. We have experienced the swarming of Asian lady beetles that will crawl into crevices of homes and that look alot like a native ladybug. These are believed to have first arrived in the United States in 1916. Southern farmers reintroduced them in the 1980s to control pecan aphids. We once captured the lady bugs emerging indoors here in Springtime and relocated them to a treasured replanted live Christmas tree that had developed an aphid infestation.

The wasps are reared in a US Animal and Plant Health Inspection Service laboratory in Brighton, Mich. To date, 180,000 wasps have been released in nine other states, including Michigan, Illinois and Minnesota under permits granted by the inspection service, an arm of the U.S. Department of Agriculture. The first wasps used in a field trial were in Michigan in July 2007. Tiny wasps have been used to control gypsy moth populations.

Traditional Potawatomi Black Ash Basket ~ Nancy Krogmann of Whitepigeon Baskets

Traditional Potawatomi Black Ash Basket
~ Nancy Krogmann of Whitepigeon Baskets

The Potawatomi Indians of Michigan have been on the front lines of the battle against the Emerald Ash Borer. Their native tradition includes making a cultural style of basket from Black Ash trees. For generations the Potawatomi Indians have used wood from Black Ash trees to weave baskets, teaching the skill to their young. For the tribe there is much more at stake than a side source of income. “Baskets made from Black Ash played a huge role in our tribe’s life and history. Back then, the baskets were like money. You traded for it, and got the things your needed to care for your family” says Jamie Brown a part-time basket weaver who is part Potawatomi.

She learned basket making from her parents. Her mother learned the skill from her uncle. So there are at least three generations of her family that have made these baskets. She adds that “It’s part of who we are. It’s cool to carry on the tradition and share it with the next generation.” The USDA Forest Service research team has discovered that the Potawatomi Indian’s traditional method of storing Black Ash logs by submerging them in rivers can effectively preserve the logs for basketmaking while simultaneously KILLING the Emerald Ash Borer larvae lurking under the bark which then prevents the emergence of adult beetles in spring. A study concluded that submerging the logs for 18 weeks during winter or 14 weeks in spring killed the insects and retained the wood’s quality for basketmaking.

Thus the arrival of the insect onto their lands was taken quite seriously by the tribe. While the Pokagon Band of the Potawatomi tribe has used insecticide on its trees in the Hartford and Dowagiac regions, they are participating in the introduction of wasps as predators in their battle against the decimation of their ash trees by the Emerald Ash Borer.

Rachel Carson with Silent Spring bookcover

There are many potentially invasive insects listed at the Missouri Dept of Conservation’s page for the Emerald Ash Borer. Interestingly, they are all types of beetles from Asian Longhorn to June Bugs to Lady Beetles and more. A healthy and diverse forest with a healthy and diverse wildlife contingent will help any forest to survive the occasional arrival of undesirable insect guests. As Rachel Carson pointed out repeatedly, graphically and so very well in her 1962 book Silent Spring – natural deterents to such threats are the best approach and chemicals should be used only sparingly or not at all because any lethal chemical will have impacts beyond the intended targets. We have noted that after a large swarming of Lady Beetles here that over the years the quantity has naturally diminished to a point where their presence is less disagreeable. Just like the weather, insects have natural cycles that will seek balance with their environment over time.

Often too, the role of the beneficial predators has not been adequately studied. The use of chemicals is motivated by profits and easy availability. However, surveys of agricultural systems give an indication of the potential number and diversity of predators in a crop. For example, over 600 species of predators in 45 families of insects and 23 families of spiders and mites have been recorded in Arkansas cotton. Eighteen species of predatory insects (not including spiders and mites) have been found in potatoes in the northeastern United States. There may be thousands of predators per acre, in addition to many parasitoids. Although the impact of any one species of natural enemy may be minor, the combined impact of predators, parasitoids, and insect pathogens can be considerable.

It is also worth noting that the efforts of bird-watchers truly make a difference in helping to advance science. According to Koenig, data from Project FeederWatch and similar efforts “play a critical role in almost any attempt to assess the populations of animals at large geographic scales as well as the ecological consequences of an invasion such as that of the Emerald Ash Borer. Given the increasing prominence of such phenomena, citizen science projects such as FeedWatch and eBird are likely to play an even greater role in the future!”

~ Information Resources

“Emerald Ash Borer Management” posted at the Missouri Dept of Conservation website –

“Emerald Ash Borers vs Woodpeckers (And Nuthatches) posted 07/21/14 by Meredith Mann at 10,000 Birds –

“Biological Control – Predators” posted at Cornell University – College of Agriculture and Life Sciences –

“Natural U.S. Predators Discover the Emerald Ash Borer” posted 08/21/13 at Wood Acres Tree Specialists –

“State to send wasp hit squad after emerald ash borers” by Lee Bergquist posted 05/05/11 in the Milwaukee-Wiscondin Journal Sentinel –

“Pokagon Band uses wasps to save its trees, tradition” by Landa Bagley posted 08/28/15 in the South Bend Tribune –

“Basketmakers’ Tradition of Storing Black Ash Logs in Water Effective in Killing EAB” posted 07/18/15 in Native News Online –

“Submergence of black ash logs to control emerald ash borer and preserve wood for American Indian basketmaking” posted 06/27/15 by the USDA Forest Service Research Station in Lansing MI available from Wiley Online Library –;jsessionid=0AADC6B0F5BCE545F153F2306C8EB2DA.f01t02

Information about volunteering to participate in Project FeederWatch is avaialable at The Cornell Lab –

eBird uses global tools to report and make information about birds accessible – learn more at eBird –


Blog author ~ Deborah Hart Yemm is co-founder of
Yemm & Hart, a green materials producer


Spring Planting in the Forest

Bare Root Seedling in Plowed Groove

Bare Root Seedling in Plowed Groove

I thought I’d share my family’s story as a way of explaining why I never got around to posting a blog here last week. My family has spent most of the last week planting trees. Back in 2002, we entered into a federal government program to reduce soil erosion and contracted to have 18,000 mixed hardwood trees planted in the riparian buffers of our major perennial stream. For two years after that, my husband mowed between the rows of trees because we refused to use herbicides to kill off the Fescue and that was the compromise we had arrived at with the government to allow us not to do that and still receive their financial assistance. My husband also walked the rows each year and hand-planted seedlings to replace any of the trees that had died with new trees. During that phase we added in evergreens and the flowering trees, Dogwood and Redbud.

It was during that time that I was pregnant with our youngest and we were searching for a name for him. For personal reasons related to his siblings, my husband wanted a name that began with “T”. We have a lot of awesome rock here on our farm and one day he came home to me after some hand-planting work and said – “I have it !! We can name him Tree Stone !!” I said no, no, no that is not a proper name and then inspired said, “Let us call him Treston”. And that story in why in some of our most fun and humorous moments we will sometimes refer to him as “Tree Stone” or “Plant Rock”.

Last year the crazy restrictions and conditions for receiving state government assistance to plant more trees caused us to abandon that plan after many hours of researching and planning by my husband because it simply did not make economic sense (it was going to cost us a lot of money that we did not have at the time) and the risks it entailed (having to repay monies received and even pay penalties on it) if we did not perform precisely as instructed were simply not acceptable. Encouraging us even more, was the fact that the contractor who was supposed to do that work for us, simply would not return our calls. It was too large of a project to go forward with all things considered. So my husband and two sons hand-planted 500 evergreen trees. This caused my husband to grow concerned that he would not live long enough to fulfill his vision of replacing our pastures with new forest with what remains of his own lifetime at such a pace.

My husband has been in the midst of this year’s project for months with lots and lots of planning in advance. We even spent an afternoon with an older man and his wife in a neighboring county. Interestingly, we first met this man back in 2002 but decided not to work with him because his values at the time did not seem aligned with ours. Now this year, my husband sought to learn everything he could from this man’s experience in machine planting trees. Not only did we visit him but several times my husband had long telephone conversations with him before we were ready to move forward with financial investments into this year’s planting.


We bought an implement for tree planting. My husband modified it to make it safer and more useful for including our youngest son in the family project even including a seat belt for him. Beginning in late February, after we had already ordered and paid for this year’s bare root seedlings, we had almost 3 weeks of snow continually on the ground – first 7″, followed by 5″. We had lots of single digit and teen temperatures during that time and there was a very, very slow melting of that snow, immediately followed by a significant rainfall.

When asked about when I thought we should pick up our trees and begin planting, I had suggested to my husband that he not pick up the trees until this week. However even though I thought we needed more drying out time but he went ahead picked the trees up at the nursery last week. Now the clock was ticking against us for the trees need to be put into the ground as quickly as possible once they are out of cold storage at the nursery. My husband still made good use of the extra “early” days by doing some replacement hand-planting of the rows that he and our sons hand-planted during last year’s effort and also hand-planting 25 Cypress trees into a wetland area.

Suburban Stuck in the Mud

Suburban Stuck in the Mud

By Sunday, we tried to start planting Walnuts according to his plan which was to start in the bottoms near some of the trees we had planted back in 2002. The field was simply too wet. I immediately got our Suburban stuck. At least we managed to do all the training sessions that first day – mine for shuttling trees and water, my oldest son for driving the tractor and my youngest son (age 10-1/2) for managing the seedlings, handing the appropriate trees to my husband and telling him the moment to “plant” in order to keep a specific distance between trees and our son’s instructions included picking a “wildlife” specie to be interspersed after every 6 hardwood trees.

Springfield Planting Plan

Springfield Planting Plan

You can get an idea of scale by noticing the little house in the red square at the bottom left of this image. This is only about half the entire length of this particular field. We will plant the other half in some subsequent year.

My older son, Simeon, was in charge of driving the tractor.

My older son, Simeon, was in charge of driving the tractor.

Eventually the impossible wetness of the field caused my husband to give up on the idea of getting any more planting done other than a very tiny start we had made on Sunday afternoon. He’s a pretty persistent, determined kind of guy so giving up entirely wasn’t easy for him to do but the reality could not be denied. The drag of the plow on the planter in that mud would cause the tractor’s tires to spin even though thankfully the tractor never became stuck so that we ended up with a bigger problem on our hands. We didn’t even try to go out to plant on Monday but gave the fields a warm dry day to become more workable. Then, our oldest son (age 14) suggested that we really ought to start at the uphill part of the field or at least in the middle. My husband was able to agree to a Plan B to plant in the middle of the field but in an attempt to keep the spacing on his original plan, he went out and flagged the spacing for two of those rows according to the downhill Walnut row.

On Tuesday afternoon, we went out and started uphill from the middle with the Northern Red Oaks and managed to get through the Black Gum after about 4 hours as the cold wind and approaching darkness put an end to that day’s work. On Wednesday, we expected rain by 2pm for the next 48 hours and so we got an early start, expecting to have to quit early. The field was the driest yet and so we turned back downhill from the middle. Good fortune kept the rain at bay and we ended up being out there for 9 hours until dark. There were some light sprinkles that came but nothing strong enough to put a stop to the day’s work. However it did rain that night and was lightly raining on Thursday.


So on Thursday, my sons and I were given the “day off”. My husband went out and hand-planted the “wetter” areas that gave us so much trouble on Sunday (the Walnut rows) by hand. He admitted that it would take many weeks for that area to actually dry out. On Friday, we got an early start – not as early as Wednesday but still put in 7 hours (working until dark). We finished the big field but still had a lot of seedlings left over, so we went to Plan B below for the excess trees.

Halcyon Planting Plan

Halcyon Planting Plan

By the end of Friday, there were only 300 trees left and so my husband and older son took care of them in about 2-1/2 hours on Saturday and allowed myself and the youngest son to stay home. These trees went into the field to the northeast of my deceased in-laws old log cabin.

Here’s the tally for this year.

Total Hardwood Trees = 2,350. About 200-300 per species. The mix included – Black Walnut, Black Cherry, White Oak, Mixed Hickory, Shumard Oak, Sweet Gum, Northern Red Oak, Black Gum, Black Oak and Chinkapin Oak.

Total “Wildlife” Species = 360. The mix included – Black Chokeberry, Black Locust, Eastern Wahoo, False Indigo, Flowering Dogwood, Red Mulberry, Redbud, Slender Bushclover, Smooth Sumac, White Fringetree and Wild Plum.

And another 25 Cypress trees in the wetlands area.

15-03 Post-planting Closure

The work is not yet entirely complete. As I write this, my husband is back out in the field on the tractor because we can’t leave the plowed groove “open”. The little rodent like critters would utilize that as a “highway” to munch on the roots ending the future of our trees. The diagram above represents the slow and tedious process as he uses one of the front tires on the tractor to close the plowed grooves. The dots represent seedlings in a row.

The long-range overall plan is to replant all the Fescue pasture that my husband and in-laws created back in the late 1970s/early 1980s in trees so that we won’t have to burn the fields to keep them open anymore. We will do that planting over about 5-6 years time in sections of about the same size or quantity as we did this year. By doing this intentional planting, we are modifying what Nature would do in returning fields to forest. In the natural cycle, Cedars, Locust, Sumac and Persimmons are among the first to take root in a fallow field. We have stands of tall Pines here that are described as succession trees, these are what grow next in the areas that once were crop fields. Later on the hardwoods begin to take hold. This cycle would create some marketable timber after 100-150 years of time elapsed.

At this time, hardwoods have the most commercial value as timber. We have planted a lot of hardwoods including quite a few species of Oak which do well and are native here. We are protecting the farm in perpetuity as long as there are descendants to live here as stewards of this extraordinarily beautiful land. Our sons will certainly be able to follow our Forest Management Plan which will have them in another logging cycle in about 30 years and therefore, they may achieve the long-term funding benefits for the continuation of this farm twice in their lifetimes. The trees my sons have been involved in planting may benefit them at the end of their lifetimes or will be of financial usefulness to their children some day.

Most people do not have such a long-view regarding what they do on the land they have possession of. I believe that is why it is somewhat rare for anyone to put so much time, effort and money into planting trees – they see no personal benefit in doing so. Certainly, serious environmentalists will always consider planting trees beneficial for the planet and all her creature’s health and vitality.


Blog author ~ Deborah Hart Yemm is co-founder of
Yemm & Hart, a green materials producer