The third of a three-part series by David Hawke concerning invasive species.
Due to several requests from readers this week’s column is, again, about invasive species. For the past two weeks the topics have been dog-strangling vine and gypsy moth caterpillars, and these ‘bad boys’ have certainly caught the attention of many residents. The following is bit of background as what you might be able to do to control their presence.
As with any invasive species, if you feel it needs to be controlled then you really need to do your homework before investing in an army surplus flamethrower or 45-gallon drum of herbicide. There are both practical and philosophical considerations to be mulled over (and if you mull them over long enough maybe the perceived threat will have gone away by the time you spring into action… but I’m getting ahead of myself).
A while back, when I was first confronted with having to deal with invasive species, a six-step plan was created that still seems to cover the situation.
Step 1. Remain calm. Sounds silly but it is important not to panic as quick decisions may result in your actions doing more harm than good. Deep breath, do your homework, come up with a plan. And this is needed whether you are trying to save one ornamental shrub or a 1,000-acre ecologically rare habitat. I acknowledge that many of us have a deeply rooted desire to “do something”!
Step 2. Pick your battles. If you think you can eradicate a species from an area, you are setting yourself up for a frustrating disappointment. In the end, the invading species will remain “out there, somewhere”. However, if you downscale your expectations to control rather than eradicate, a small victory may be within your grasp. If you can keep your property under control, that is a good thing; if you want the whole neighbourhood or township cleansed… just not going to happen. Remember the Dandelion Wars… still raging since the 1950s.
Step 3. Plan your attack. This involves getting to know your enemy, including accurate identification, its life cycle, its weaknesses. Research what others have done to thwart this particular species… the Internet is chock-full of background information of invasive species in general and whatever is giving you nightmares in particular. Learn about options, methodologies and successes of others. And read the label.
Step 4. Stick to the plan (unless, of course, things change). Consistency of suppression will help you attain that lofty hope of cleansing the yard of Species X. If you spray lightly, or only dig out part of the patch, you might as well have done nothing. Attack like you mean it: hit it hard and monitor closely for survivors. All the while you should be open to learning about new techniques (maybe pouring boiling water on that plant is just as effective as spraying a jug of nasty chemicals). Alter the methodology but be consistent in your efforts.
Step 5. If at first you don’t succeed… pull, pull again. Battling invasive species is not a one-hit Sunday afternoon project. With plants you will be fighting a seed bank, that reality of there being hundreds or thousands of seeds already lying dormant in the soil, each one germinating in its own sweet time, sometimes 10 years after falling to the ground. In the case of garlic mustard, if you miss one year’s removal, if you miss one seed pod, the clock goes back to zero and you have another 10 years of monitoring and pulling to do.
Step 6. The goal is control. As mentioned, eradication is not going to happen. But if you can control the spread and density of Species X by removing or preventing the establishment of new seeds or new generations, then you deserve that cool beverage at the end of the day.
Now comes the philosophical side of the problem. One, are the invaders really a problem? And, if so, are there other options to take besides lethal warfare?
This year the caterpillars of gypsy moths have reached epic proportions and have defoliated entire woodlots (especially up around Tiny Township). This is a natural cycle of this species, a rising and then falling of population over several years. When they are bad, they are really bad… your once shady patio becomes a green mat of caterpillar poo while overhead the sun shines through.
So, you want to fight back. Yes, there are different ways to do so, from wrapping the tree trunk in sticky tape (the caterpillars come down from the canopy to rest for the day), to flicking them into a bucket of soapy water, to employing a small aircraft to drop deadly spray across the forest canopy, to frying them with a hand-held blow torch. Or you can do nothing save sweep the patio and put up shade umbrellas.
My scenario with gypsy moths is admittedly unique: Eleven years ago, we planted 900 red oaks on our farm, in nice straight lines. The plan is to grow a truckload of perfect of veneer quality logs that my great-grandchildren may sell to the highest bidder. I have laboured long and hard to ensure the seedlings have grown tall and healthy. But now the compartment is full of gypsy moths, big fat ones, eating the leaves of my precious oaks.
So I, having a strong urge “to do something” have totally avoided following my own six-step plan and have rashly purchased a small propane cylinder and over the past week have daily walked the rows, frying the nasty vermin found resting on the tree trunks. (This has to be done with great care as the heat must be intense enough to cause immediate demise of the targets without causing harm to the inner bark of the tree.) Bwa-ha-ha, I’m going to get you!
As my Good Wife pointed out, I cannot possibly kill all the caterpillars, and by eliminating a portion of the population am I not ensuring the survivors now have less competition and therefore will mature, mate and lay eggs in strong numbers? And if I kill only the caterpillars that are within my reach, won’t the survivors that stay higher up be the ones reproducing and won’t their offspring tend to stay high due to genetic evolution?
Well, yeah, but, you know, I have to do something, right?
Pick your battles. That thought goes beyond invasive species… sometimes it creeps into matrimonial conversations.
David’s notebook: A bit of rain does wonders doesn't it? I hope your garden recovers and your lawn turns green once more.
Photos by David Hawke: Seed pods of the dog-strangling vine; gypsy moth caterpillars
© 2020 David J. Hawke