Going half way around the world to take on the mile-a-minute weed

Last fall (October 2010) I went to China for the first time.  I was invited by Chinese colleagues who obtained funding for a tour involving me and other weed science colleagues from the U.S., Australia and Japan.  The government of Yunnan Province is very concerned about this weed, and is funding efforts like these to understand how to stop mile-a-minute weed (otherwise known as Mikania micrantha) from growing out of hand.


From left to right: Prof. Fudou Zhang (Yunnan Academy of Agricultural Sciences), Dr. Joseph DiTomaso (University of California, USA), Shicai Shen (YAAS), Wu Di (YAAS), Dr. Hisashi Kato (Kagawa University, Japan), Dr. David Clements (Trinity Western University, Canada), Dr. Leslie Weston (Charles Sturt University, Australia), Ruili City colleague, Dr. Tianlin Li (YAAS), Ruili City colleague.  Behind us is a lemon tree orchard being smothered by mile-a-minute weed (Mikania micrantha)

The first encounter we had with the weed, just outside Ruili City, Yunnan,  was in a lemon tree orchard that had been decimated by Mikania.  The infestation of Mikania had been sprayed with herbicide that spring, but the weed had regrown from roots in a few short months to once more overwhelm the lemon trees.  We found few signs of life among the sorry lemon trees overtaken by the Mikania  vine.

This damage has been repeated across many locations and many crops and natural areas of Yunnan Province, and it is predicted to continue to spread.  It just began invading Yunnan in the late 1980s and has already swept through much of Guangdong Province.  Mikania utilizes a two-pronged strategy to rapidly spread and conquer.  Firstly, its seeds are small and light with wings for aerial dispersal and it produces a lot of them – as many as 170,000 per square meter where the vines are actively growing.  Secondly, once the seeds germinate in an area, it is capable of rapid growth and as vines extend outward they are capable of forming roots from the stem.  So a single foothold by a Mikania seedling quickly becomes octopus-like and worse.

So what can be done?  Should we just give up trying to keep up with the mile-a-minute weed?  Or should we just resign ourselves to trying not to let the problem get worse?  Is there in fact hope that the spread of Mikania can be reversed? 

Part of the answer to these questions is that it is very important to allocate resources to fighting the battle, as Yunnan Province is doing.  Over here in sparsely populated Canada, it is hard to imagine what a country with 1.3 billion people is like, but I came away from my first visit with a real appreciation for the needs of the Chinese people who need to deal effectively with threats to their food supply, such as Mikania.  Harvard Biologist E.O. Wilson makes that point in his book The Future of Life on Earth saying if catastrophic harvest losses occurred in China, it would be very difficult for the rest of the world to compensate.  We are seeing more and more how in every arena of the new global economy that China shapes what happens in the world.

The other major response I have to these questions is inspired by spending a week with my Chinese colleagues.  I take much hope from my new friends in China.  They have dedicated their careers to strategically studying and thinking about the best approaches to the problems posed by these weeds.  We spent many hours travelling through the Chinese countryside, eating wonderful Chinese food together and brainstorming on approaches for managing Mikania.  These Chinese colleagues on the front-line of the battle have been equipped by their creator with discernment, boundless energy and determination to enable them to help bring order back into creation.  Right now the progress seems to be only measured in inches, but I trust that in time, progress will be more like a “mile-a-minute.”


Last updated Mar. 1st, 2011 at 9:41pm by David Clements