Insidious Insects? Or Pleasant Pollinators?

Our chickens love bugs.  Crickets, grasshoppers, dragonflies, wasps, spiders, junebugs, roaches, beetles, butterflies, if it creeps or crawls, they will joyfully scoop it up and do a victory lap around the coop, whether the other chickens notice them or not.

Like most people, the very word “bug” has always conjured up for us an image of nasty creepy crawlies, and the idea of the chickens eating said critters cheers us greatly.  However, bugs are more complicated than that, and their relationship to a healthy garden is also much more sophisticated than a cursory and prejudicial review might indicate.

We have mentioned before that we intend to install an apiary some time soon; we have a wild honey bee hive on the property at present, and we would like to move the bees from their present home to a box where we can get at their honey; we’d ideally like to have a couple of boxes, and go into small-scale commercial production of the golden stuff.  It doesn’t hurt that bees pollinate fruits and vegetables, either.

However, in researching bees and their role as pollinators, we have discovered that the equation is not so simple – there are important limitations on what bees can and cannot do for a gardener, and there are subtle relationships between various plants and insects which must be respected.  Some bugs, like honey bees, are vital, but do not do everything we always thought they did.  Other bugs, like bluebottle flies, are annoying as all get-out, but do some helpful things we never thought they could.

Anecdotally, one of the more remarkable prejudices we have personally been forced to face down comes from literature.  When reading Barbara Kingsolver’s Poisonwood Bible, we remember thinking it highly unlikely that the story of an American missionary being unable to grow familiar garden vegetables in Africa due to a lack of pollinating vectors could possibly be true.  Sure, African bees would be unfamiliar with American veggies, but a flower is a flower, right?

Wrong.

As it turns out, the relationships between insects and plants are intensely affected by geometric, chemical, and photochromatic concerns, all of which should be kept in mind by gardeners who, all too often, reach for the can of Raid any time the buzz of six-legged ‘interlopers’ is heard.

As an example, the most popular plant in the American backyard vegetable plot is the tomato.  If you grow any vegetables at all, this is likely to be the first one you plant.  And we are all familiar with the bright yellow tomato flower.  You may assume that if you have honey bees, you will have no problem with tomato pollination, but you would be wrong. 

Tomatoes must be “buzz pollinated”, meaning that in addition to having a bug land on the flower, the bug must generate sufficient vibration from the flapping of its wings to dislodge the pollen; honey bees are incapable of this degree of vibration.  Bumblebees, however, do the job quite well.  As do bluebottle flies!  If you don’t have bumblebees, the odds are your tomato crop is successful only if you have enough flies; something to think about at your next picnic.

Red clover is another popular plant with which honey bees can’t do a thing.  The flower is too deep for them to reach the nectar, and as a consequence, they never get the pollen stuck to their legs, and so never take it to the next plant.  Some bees (again, the bumblebee being prominent) have longer tongues, and can pollinate red clover.  Some moths and butterflies, too, love this cover crop.

There is a whole field of research devoted to maximizing the ability of vectors to pollinate certain crops in certain conditions.  There are even researchers who are investigating the proper means of covering a greenhouse where certain species of bee (who navigate via their vision of ultraviolet light, with which glass or plexiglass greenhouse walls usually interferes) must be contained.

The more holistic the researchers, however, the more successful they seem to be.  Beneficial insects and pest species really ought not be considered separately; the whole ecosphere needs to be taken under advisement when thinking about how to best manage your garden.  Book 7 of the handbook series from the  Sustainable Agriculture Network – National Outreach Arm of USDA is entitled Manage Insects on your Farm:  A Guide to Ecological Strategies, and it offers this advice:

• Select and grow a diversity of crops that are healthy, have natural defenses against pests, and/or are unattractive or unpalatable to the pests on your farm.  Choose varieties with resistance or tolerance to those pests.  Build your soil to produce healthy crops that can withstand pest pressure.  Use crop rotation and avoid large areas of monoculture.
• Stress the pests… Interrupt their life cycles, remove alternative food sources, confuse them.
• Enhance the populations of beneficial insects that attack pests.  Introduce beneficial insects or attract them by providing food or shelter.  Avoid harming beneficial insects by timing field operations carefully.  Wherever possible, avoid the use of agrichemicals that will kill the beneficials as well as pests.

These are the fundamental building block steps to achieving balanced management.  Pests should not be eradicated, they should be gently led away from those places in which you do not wish them to be.  Control is always an illusion; the best we can hope for is to take advantage of predictability. 

If you know, for example, that you want more bumblebees in your yard because you have a large crop of tomatillo plants which flower like crazy, but have not yet produced fruit, the answer is fairly obvious:  plant red clover.  The bees love the clover, but they will also eventually notice your tomatillos.

If you want to reduce the population of Colorado potato bugs who are munching on your tomatoes, attract some beneficial bugs like the Assassin beetle by planting a cover crop of hairy vetch, crimson clover, or rye.

Improving the quality of your soil, too, reduces the need to worry about whether your plants are being attacked by any sort of pest.  From Manage Insects… again:

“Healthier soils produce crops that are less damaged by pests.  Some soil-management practices boost plant-defense mechanisms, making plants more resistant and/or less attractive to pests.  Other practices – or the favorable conditions they produce – restrict the severity of pest damage by decreasing pest numbers or building beneficials.”

Further, even where pests persist, healthy plants are not likely to be taken down by them:

“Practices that promote soil health constitute one of the fundamental pillars of ecological pest management.  When stress is alleviated, a plant can better express its inherent abilities to resist pests.  Ecological pest management emphasizes preventative strategies that enhance the ‘immunity’ of the agroecosystem.  Farmers should be cautious of using reactive management practices that may hinder the crop’s immunity.  Healthier soils also harbor more diverse and active populations of the soil organisms that compete with, antagonize, and ultimately curb soil-borne pests.  Some of those organisms – such as springtails – serve as alternate food for beneficials when pests are scarce, thus maintaining viable populations of beneficials in the field.  You can favor beneficial organisms by using crop rotations, cover crops, animal manures and composts to supply them with additional food.”

For most of human history, the prevailing motif has been the casual acceptance of the idea that “Man vs. Nature” is an unending battle which we have no choice but to enjoin.  That paradigm is a roadmap to extinction, not just for all the species left in our wake, but also for ourselves.

We cannot haphazardly poison half the planet just to try (and fail!) to rid the other half of particularly pestilential potato bugs.  True wisdom in pest control lay in the question “What is the least amount of force which will work?”  In that regard, gardening is a lot like parenting.

Sometimes your garden even talks back.  And, as with your children, it might be a good idea sometimes to listen, instead of complaining about their “backtalk”.  Your kids are smarter than you give them credit for.  So are your bugs.

Happy farming!