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Wednesday, May 13, 2015

Pests In Paradise

Our adventure started here after an 8-mile hike to Snowmass Lake near Aspen, Colorado
(originally posted on Forbes, 5/11/15

I learned something very important about crop pests in a most unexpected setting – a paradise-like wilderness area in the Colorado Rockies.  It was the summer of 1978 and I had gotten married the year before. This was my first chance to share a favorite place, the Snowmass/Maroon Bells Wilderness Area, with my wife.  We backpacked into Snowmass Lake and day-hiked to high passes through huge meadows filled with beautiful wildflowers.  However, on this trip, I noticed details I had never observed on earlier visits as a suburb-dwelling teen.  With “new eyes” from my first year of agricultural training, I saw that many of the plants showed signs of insect feeding damage or gall formation.  They exhibited symptoms of fungal infection – such as rusts and leafspots.  There were pests in this paradise! And they were host specific – not interlopers carried in on the boots of visitors like us.
View from Buckskin Pass
Thinking about it, I realized that this wasn’t really surprising.  Plants have the unique “super power” of turning sunlight, water and carbon dioxide into the food that directly or indirectly feeds everything else – including us.  It makes perfect sense that insects and fungi have evolved to “harvest” that energy, in even this pristine ecosystem.  I then realized that what we call “pests” are simply part of the natural order.  Thus, it is to be expected that we often have to find ways to deal with “pests” of cultivated crops.  The need for pest control isn’t an artifact of human farming. Practical farming needs may complicate pest control, but the basic phenomenon of pests is entirely “natural.”


On one hand, we might say that a “pest” is simply a human concept for cases where this natural phenomenon interferes with our agenda.  However, it seems that plants “agree” with our assessment that these damaging, dependent organisms are pesty. Plants are obvious targets, but they don’t just take it.  I once heard a presentation about the genetics of a particular alpine wildflower that grows in exactly the same kind of meadows we were visiting in 1978. This species has genetic “factions” employing two different strategies to deal with insects that want to eat it.  One is to put energy into rapid growth and seed production, so that even with bug damage, the species survives.  The other strategy is making chemicals to protect the plant from the bugs, leaving less energy for seed production.  Depending on the season, one strategy or the other is more successful.
Chemical defense is common among plants.  In some cases we have come to like the pesticidal chemicals they make. The caffeine in coffee and the capsaicin in hot peppers were “intended” by those plants to ward off “pests.”  Many vegetables we enjoy, such as tomatoes, eggplants and cauliflower, still make some of a not-so-nice “natural insecticide” called nicotine.  But don’t worry. You would have to eat an enormous amount to be hurt by the nicotine, caffeine or capsaicin.
So since pests are part of the natural order, and since plants fight back with their own “pesticides,” human use of pesticides makes sense as part of a pest management strategy for the plants we tend.  That is particularly true now that we have developed many products that are quite specific for certain pests, and very low risk for us or for the environment. Pesticides are also necessary tools for those farming under the organic rules.  Synthetic pesticide residues are present at even less consequential levels in our produce than plant-made chemicals.
A slightly modified quote from the Princess Bride (modified from https://www.pinterest.com/lemai13/the-princess-bride/)

If you have the chance, I encourage you to visit those Colorado wildflower meadows.  They are beautiful, and unless you look for it, you probably won’t notice the battle between plants and pests that is going on in the background.  The wildflowers survive, even with the damage.  The season is also short, so there are not many generations of the pests. We humans require a higher standard of pest protection for our crops. To make the most responsible use of our land, water, fuel or other inputs, we cannot tolerate too much pest damage or the crop is diminished.  Besides, as even my grand daughter realizes, pests are yucky!  

You are welcome to comment here and/or to email me a savage.sd@gmail.com