Often, when talking about Integrated Pest Management, we speak of concepts like plant diversification, low maintenance design, monitoring, proper scheduling and sustainable cultural practices. Consider this though: over the past century, the tree epidemics of Dutch Elm Disease, Asian Long-Horned Beetle, Hemlock Wooly Adelgid and Emerald Ash Borer have all migrated to the American landscape riding on the machine of global trade.

These pests have arrived under the illuminating torch of Lady Liberty, unknowingly by customs officers at the time of course, in wholesale wood products, pallets and the likes of these secondary packaging vectors. In this sense, global trade has affected IPM management in catastrophic ways, in ways that are often not put under the laboratory microscope. Many, many millions of dollars have been raised in order to research and fight against these crippling infestations that have threatened some of our most beloved shade and street trees in the American urban forest.

Logistics, then, is the culprit, when talking about large scale pest infestations. So to say that planting the right tree in the right place is the answer for low maintenance seems absurd-almost too easy of a way out of the conversation-when considering the powerful global market and the force that international trade has on spreading dangerous, foreign pests to new soil.

The Ash, the Elm, the Hemlock, are all examples of trees that provide strong roots in the urban forest. All three tree species, have faced cataclysmic decline because of invasive pests, mainly from Asia, a huge exporter to the American economy.

But economics is hardly ever the topic of concern when it comes to IPM management. In fact, when talking about IPM management, one of the main tactics arborists concern themselves with is preventative controls. Which is ironic, in this discussion. I’ll quote ISA’s BMP on Intergrated Pest Management which reads: “Preventative tactics are vital to a sound landscape IPM strategy. Plant selection and cultural practices are key preventative tactics used for managing landscape pests. They are used to achieve two basic pest prevention goals: 1. Minimize plant stress by encouraging favorable plant development conditions. 2. Minimize pest activity by discouraging favorable pest development conditions” (14).

We have failed to address invasive plant pests on a global scale, and so we have failed to use preventative measures, as ISA defines them in the BMP, to the best of our abilities.

We know that Elms, and Ash especially work well in the urban environment because they grow on a variety of sites and are tolerant of many stresses in the urban forest (ie. site alteration, variety of soil structure, mechanical damage, etc.). So proper site selection and favorable conditions, it seems, is a strong argument for pest control. But when considering the threat of foreign pests that are impartial to the economic importance of a specific species like Ash and Elm, site selection and proper cultural care mean next to nothing when we live in a global economy that can literally overnight a pest capable of wiping out an entire species.

In a foreign factory somewhere, a pallet is being built to ship a clock or a box of t-shirts or whatever the product may be, and inside those wood fibers is a new pest, sleeping a wooden cavity, unknown to anyone here in the American landscape, that has the capabilities of wreaking absolute havoc on tree species that are near and dear to the city streets and memorial groves of our urban forest network. That little larvae is molting and morphing and chewing its way slowly out of the wood, and absolutely no one knows about it yet. And when we find out, as historically has been the case, it will be too late. 100,000, or 200,000 trees already breeched and in decline, we’re desperately searching for a new active ingredient, a new biological agent, a new cultivar that is resistant.

But we missed them at the port.

The BMP tells us that “on the pest side of the equation, it is also important to mitigate landscape conditions that promote pest development or activity. Many pests thrive under adverse site conditions including extreme of temperature, moisture, and light, as well as misguided management practices…” (14).

So we can consider global trade, in a sense, to be a misguided management practice on many levels.

My thought is this: our dependence on foreign markets and the global economy have directly impacted our fight of invasive pest species in the urban forest. The more we depend on foreign economies for trade, the more at risk we are of introducing foreign pests to our native tree species in which we are incapable to dealing with efficiently. When looking at IPM management, arborists need not get hung up on the landscape that is directly outside our window, or down the street. For that is a landscape we can easily master. The present setting is a technologically-rich modern arboriculture. And maybe we don’t do a great job of bridging the gaps in global trade. For that is the weak link, and that is what is encouraging the spread of invasive species on a global scale as far as what products we are shipping, and the infrastructure we are building to support that trade (i.e.. products that actually carry the products).

Sustainability as a national economy could be a new perspective on IPM.

So, at it’s core, global trade is a major Abiotic stress factor when it comes to the last hundred-year history of battling major invasive pests. In modern times, the global market has done amazing things for trade, business and commerce. But it is a breeding ground for the transportation of insects, and it is a perfect vector for their voyage into the heart of a far away, distant forest, tree lawn or backyard. In the new world, there is promise and opportunity for invasive species to thrive and succeed.

And so global trade, when considered from the perspective of certain at-risk tree species, is a key link to the introduction of opportunistic pests that cause damage on a national scale, and economic and environmental loss of unimaginable scale. The global market itself is a direct abiotic stress that can potentially threaten the heritage of our most valued species. Therefore, monitoring needs to evolve with this current global market. The plant health care community needs to focus not only on the local landscape, but on foreign shipping, manufacturing and trade on a microscopic level. The integration of pest management should move far beyond the landscape, and into every detail of world-wide trade.

If not, history will just repeat itself.