Bt Pesticides: Friend or Foe?

As 2011 draws to a close, many of us have begun planning our 2012 gardens. Many of you have probably already harvested and stored seeds from this year’s crop and are looking into ordering heirloom seeds for veggies that you’d like to try growing for the first time this spring.

The arrival of winter gives us time to repair our equipment, sharpen our hoes, and check our supplies. In addition to laying in a good supply of a naturally balanced organic fertilizer like Protogrow, many gardeners stock up on organic pesticides while their garden is hibernating. Over the past few decades or so, Bt has been a popular choice among folks who like to grow organic produce.

Unfortunately, its popularity may be ruining this once-useful tool.

Bt, or for folks who like those tongue twisting scientific names, Bacillis thuringiensis, is a natural organism that can be found at low levels in most soil in all parts of the world. Back in the days before the folks in lab coats began messing with it and other people began spraying by the ton, good old Bt had a lot of benefits over artificial pesticides.

One of its greatest strengths was its selectivity. Different subspecies of Bt impacted different harmful critters. You could find a specific form of Bt to deal with beetles, black flies, mosquitoes, spruce budworms, gypsy moths, and a few other pests. With over nineteen subspecies found in nature, Bt was fairly versatile as long as you knew what you were targeting and which form of Bt dealt with that specific problem. Although it could sometimes cause skin or eye irritation, it was fairly safe to use as long as you used a little common sense.

Like a lot of bacteria, Bt forms tough spores that help it get by when times get rough. What makes this particular bacterium somewhat unique is that it also forms protein crystals when it forms the spores. These crystals are the key to Bt’s insect-fighting power. When your target larva munches on a Bt spore, it also gets the protein crystal as part of the package. The protein dissolves in the gut of your hungry pest and produces a toxin which messes up the digestive process. To make a long story short, the once-hungry larva ends up starving to death. While Bt is effective if you catch your target insect at the larval stage, it has no significant impact on the adult insects.

So far, it sounds like Bt is a worthy gardening ally. Unfortunately, like a lot of things, the Bt situation has become a bit more complicated in recent years. We’ve begun seeing companies promoting rare Bt strains that are “performance-enhanced” and/or genetically modified. At the present time, we have no idea what how these unnatural strains will impact our soil, our gardens, our crops, and our bodies.

Messing with any bacteria is a dangerous business, but messing with Bacillus thuringiensis could be particularly harmful. Bt is closely related to Bacillus cereus and Bacillus anthrasis. B. cereus is the bacteria that causes food poisoning and, as some of you may have guessed from the name, B. anthrasis is the bacteria which causes anthrax.

Even in its natural forms, Bt secretes many of the same toxins B. cereus does when it’s growing. As the new Frankenstein strains of Bt have arrived on the scene, we’re beginning to find Bt spores in human gastrointestinal and respiratory tracts. Some scientists are beginning to suspect that some of the people who have been diagnosed as suffering from a common form of food poisoning called B. cereus gastroenteritis may actually be suffering from exposure to Bt.

To make matters just a bit hairier, most commercial Bt products are being loaded up with “inert” ingredients. These substances are said to be flowing agents, wetting agents, enhancers, and preservatives. Some companies go so far as to claim that their “inert” ingredients are trade secrets and refuse to release details. Despite that, we do know that most mixtures include sodium hydroxide, more commonly known as lye, which can damage your upper respiratory tract; corrosive sulphuric and phosphoric acids; and the ever-popular sodium sulfite, which has been shown to cause nausea, lowered blood pressure, diarrhea, and hives. Of course, that short list is just some of the stuff we know certain companies pack in with their Bt. I suspect that a more detailed analysis of each brand would reveal even more “fun” additives.

Widespread spraying of Bt products to cut down of mosquitoes, black flies, and gypsy moths has also led to another problem. Recent studies have shown increased insect resistance to many forms of Bt. As we’ve sprayed tons of this substance on farms and forests, bugs are being born that have a built-in immunity to Bt. The same product that seemed so effective five years ago might not even give your pesky larva a slight headache these days.

In the end, your best defense against garden pests comes down to growing healthy plants. That’s why I strongly recommend fortifying your soil with healthy compost and a naturally balanced organic fertilizer. Before planting next season, make sure you loosen the earth and provide decent drainage. If you haven’t cleaned up your garden after your recent harvest, make sure you take some time to do that at your first opportunity. A messy garden is a breeding ground for all kinds of creepy crawlies that will be eager to devour your tender, succulent young plants as soon as they start to reach for the spring sun.

If you insist on using a pesticide, Bt is probably still a better choice than any of the synthetics on the market, but please exercise caution. You are growing a garden to provide you and your family with a healthy, sustainable source of food, not to become part of a chemistry experiment being held to increase the profits of a few select companies. It is your garden and it is your choice but, as for me, I tend to lean towards safety and health over convenience. Controlling pests without a lot of spraying is more work, but I sleep easier at night knowing that I’m growing nutritious food.

Well, looks like we’ve come to the end of the last column for 2011. Please drop by again early next year for more musings, meanderings, raves, and revelations from my survival garden. Until then, I’m wishing you and yours all the blessings of a new year and a wonderful time planning next year’s crops.

©2011 Off the Grid News