Predator and Prey (or Do Bugs have Tastebuds?)

In conventional gardening and farming, pests are a serious topic of conversation.  Pests that are specific to particular crops can be disastrous in a monoculture: one plague of locusts and that’s the year’s income gone.  Gardening information over the last 60-70 years has generally trickled down from farming, and the panic set off by the sight of pests has often been the same in the home garden.  Panic leads to chemical warfare against pests, and chemical warfare leads, inevitably, to devastated landscapes that nature tries desperately to repair with weeds and other “undesirable” means.

When I first started reading about organic gardening in preparation for my own efforts this year, I was disappointed to see that one side of the movement was really just about substituting less harmful methods for the chemical ones.  In other words, people advocating the same approach as conventional gardening, just with different products.  It seemed a bit like the “buy your way out of economic disaster” or “become more environmentally friendly through buying more products”  or “import a bigger pest to eat your small pest” lines that we hear regularly everyday.  Doesn’t Einstein or someone have a saying that you can’t solve a problem with the same tools that created it?

Luckily, there are lots of people writing, teaching, and practicing a better way.  I’d like to call it a new approach, but that’s hard because it’s both new and timelessly old.  I’d like to do some exploring and research, one day, into just how old some of these practices are.

The alternative approach begins with recognizing that, despite our North American bias toward the focus on the individual, right down to the patch of land that belongs to ME and ME only, we cannot isolate our gardens from the wider ecosystem.  We cannot get rid of pests.  Pests (including weeds) are critters that live in our region and are everywhere.  No matter how many fences we put up and chemicals we use, we’re at best coming up with temporary reprieves.  Ecosystems are dynamic and interconnected, and birds, wind, rain, insects, etc, don’t recognize the barriers of property lines.

Second, we don’t want or need to get rid of pests.  All these critters exist because they are occupying a necessary ecological niche.  So pest management is actually not about the pest, it’s about understanding your ecosystem.  And when the system is healthy and balanced, pests cease to be a problem.  And the good news is, creating a healthy and balanced system is LESS WORK and MORE JOY than the conventional method, which requires us to be constantly second-guessing and intervening to replace the natural mechanisms.  I don’t know about you, but I definitely don’t have enough knowledge to artificially recreate natural cycles!

Here’s my most recent lesson on this.  An English visitor to my veggie garden in early spring commented on my huge, overwintered fava beans (known as broad beans and much enjoyed by the English).  He said, “my father always swore by overwintering broad beans as the only way to control black aphids.”  My West Coast Seeds catalogue (Bible #2) also commented that pinching back the tips of favas covered in black aphids would keep them at bay.  I filed that away, and didn’t see any black aphids all spring.  I saw a lot of wasps around my favas, though, and I wondered if these predators were keeping the aphids under control so well that I was never going to see one.  A tad idealistic, as it turns out!

Looks like the aphids were just waiting, like the rest of us, for the spring to warm up, because in the last week or so, the tips of several of my fava plants have indeed become covered in black.

I considered my options.  First option, do nothing and just watch.  I have two types of favas planted, the giant over wintered ones and some much smaller ones I planted in February/March.  They are two different varieties, too.  Here’s what these look like at the moment:

Hardy, healthy plants.. and rose photo teaser!

Yep, these puppies are more than 6 ft tall.  It seemed a distinct possibility that the aphids at the top might not be more than an annoyance.

Option number 2 was to give them the ol’ aphid jet spray of water.  I did try that on one plant, with some success, but the whole time, I kept thinking of the predators.  See the key to keeping pests under control is to remember that they are often the food at the bottom of the food chain.  You know, like plankton, or grains.  You need a lot of that bottom food to feed the next level of consumer, and that next consumer is always bigger, fewer in number, and has a longer, slower life cycle than the level below.  In pest terms, this means that to attract a healthy population of predators, you have to maintain a healthy level of prey, and the prey has to stick around long enough for the predator to go through its life cycle.  So even as I sprayed off a few aphids, I wondered if I should really just be looking at these guys as the potential ladybug buffet.

I looked a little closer at the blackened fava tips, and here’s what I saw:

Dun nah.. dun nah (think Jaws)

The ladybugs were on the case.

Option number 3, also do nothing.  When I looked even more closely, I noticed that some plants were covered, and, as often happens, some weren’t touched at all.  The plants that were covered were generally the same ones that didn’t have many bean pods on them, whereas the ones with lots of bean pods seemed less affected.  Besides being food for others, pests are also often the critters in charge of culling the herd of the sick and weak.  I decided that I had no trouble sacrificing the few plants–all of which are almost at the end of their time in my garden anyway–in favour of the bean harvest, which is, after all, why these favas are in the garden at all.  If I pulled out the affected plants–took over nature’s role of culling the herd–where were the aphids and ladybugs going to go?  To the healthy plants is a distinct possibility.  If I leave in the weaker ones to be munched on until all of them are coming out, hopefully everyone will stay happy.

I now understand the “trap plant” concept: keeping plants pests love to distract them from the ones you love.  Many folks suggest this is a good reason to leave some weeds around–if you’ve got nothing but your perfect, special plants about, what are the pests going to eat?

My last thoughts as I walked away, pleased that once again my solution was to “do nothing” :), was about timing and the seasons.  The aphids obviously showed up at a very specific time, I assume connected to temperature, etc.  The ladybugs were clearly happy about this.  They have been munching on the green aphids here and there on the roses for the last month or so.  I couldn’t help but wonder if the ladybugs were not like us waiting for the strawberries to ripen!  “I wish the temperature would warm up just a bit more so that those black aphids would show up; they’re my favorite spring time treat!”  As the Skipper pointed out, the birds ignored our many grapes last year until they were ripe, and our green blueberries are completely safe at the moment…. So to me, at least, this does suggest that critters might have tastebuds too, and also be guided by pleasure?  Too radical?  Anyone with pets knows that they love some foods and won’t touch others.  The goldfish in the pond LOVE the frozen bloodworms that the Skipper feeds them, and are indifferent to other foods he’s tried.  Why should humans have all the fun? 😮

Mmmmm...I love it when the black ones are in season...

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