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Every year the North Carolina Nursery & Landscape Association (NCNLA) holds the “Green & Growin’” Conference & Trade Show in Greensboro. Nurserymen, Landscapers & Educators may attend 3 days of classes plus a 2-day trade show. For those 2 days the Greensboro Coliseum is filled with trees, colorful shrubbery, tropicals, perennials, ground covers, bulbs, nursery pots, giant tractors, pruning tools and more.
I LOVE going! Besides being surrounded by hunky guys, I come away with valuable information, new ideas, and new sources of the coolest plants. Best of all, I meet some fascinating people.
One of the biggest topics of discussion this year was the use of pesticides and their effect on beneficial insects, including bees and pollinators of every kind. Dr. Steve Frank of NCSU’s Entomology (Bug) Department, had great information which I will attempt to summarize. The #1 insecticide being used today is a class of chemicals known as “neonicotinoids”. Made from the nicotine in tobacco they have become increasingly popular because of their low toxicity to mammals (us). These “neo-nics” as they are called, are listed on pesticide bottles under many chemical names (Acetamiprid, Clothianidin, Dinotefuran, Imidacloprid, and Thiamethoxam) and with Brand names such as “Safari”, “TriStar” and “Merit”. You will find some of these on the shelves of every Lowes, Home Depot and garden center in America. Companies who make these products include Bayer, Bonide, Gardens Alive!, Green Light, Lesco, Scotts, and others.
The problem is that these “neo-nics” are EXTREMELY TOXIC to bees. Whether sprayed or used as a soil drench, if it gets on a bee directly or through contact with tainted pollen, it destroys the bees antennae and eyesight, & messes with their nervous system. The bee can no longer forage or even find its hive. (Sound a bit like “colony collapse disorder”?!) Ironically, because “neo-nics” do not effectively kill aphids, mites or slugs, they will actually cause an outbreak of these bugs because you will have killed their natural predators! Neo-nics have already been banned in England and the European Union, and these chemicals have NO place in our yards or gardens either.
Unfortunately even “natural” or “organic” pesticides like Pyrethrin or neem are “broad spectrum” meaning that they kill indiscriminately any insect, good or bad, on contact. My historical favorite “Sevin” spray, another “broad spectrum” pesticide, has been proven to cause kidney disease in 40,000 rice farmers in India. (Kiss it good-bye. I’m going to miss it!) It has been banned in SriLanka along with glyphosate (the herbicide in Round-up, which warrants another full GMO discussion) and several others. Yes, they are all worse than we were led to believe. You can see why this is such a HOT topic.
SO WHAT DO WE DO about those pesky aphids, thrips, squash bugs, cucumber beetles, Japanese beetles & stink bugs? My “Aha” moment came while listening to Dr. Chris Hayes of BioWorks (www.bioworksinc.com) talk about Biological Control. What if instead of poisoning bad bugs, you could introduce “good guys” in your garden that would EAT the bad guys? What if the white hats could actually multiply faster than the black hats and out-number them?
We are talking about biological insecticides that are beneficial strains of naturally occuring fungi and bacteria. These microbes have a shorter shelf life than chemical pesticides because they are alive, and they start working best when the soil is at least 50 degrees. The timing of application is important, however one application may provide benefits for as long as 3 months.
With names like Trichoderma, Streptomyces lidicus, and Beauveria Bassiana, one would believe that these are reincarnations of Ebola. But they actually have very low toxicity to beneficial insects or people because of HOW THEY WORK to prevent problems. Trichoderma fungi actually prevent root rot and extend the plant’s root system so it grows bigger and healthier. When spores of Beauveria come in contact with the body of an insect (usually at larvae stage in the soil), they germinate, enter the body and grow inside the bug, eventually killing the pest. (Ewww!) But OK, bring them on!
Whatever garden pest is bugging you, try to identify it as specifically as possible. (Red mites? You will need a “miticide”. Mites are not “bugs” so even the tough bad-boy chemicals won’t work.) Your local county extension service can help. Then look for OMRI (Organic Materials Review Institute) listed products that are the least toxic to the environment and to YOU. Spinosad is a fairly easy to find natural insecticide made from bacteria. It is OMRI- listed, and you can check on line for detailed information. Although it is non-toxic to humans and degrades quickly in the soil, it is still toxic if sprayed on pollinators. Generally toxicity drops after it has had 3 hours to dry on the plant.
Old fashioned non-living biologicals like dormant oil and horticultural oil sprays are still great choices for smothering eggs of mites, scale, molds and preventing mildew; use it now before the weather gets hot. The high pH of Baking Soda makes it very effective as a spray for controlling mildews like the yucky white powdery mildew that covers the leaves of your squash and cucumber plants every summer. (You know it is coming!) Add one drop of dish soap to your spray to help it stick to the leaves and apply when you see the very first sign of disease. Baking soda’s high salt content also desiccates hard bodied insects. Yes, even squash bugs, if you spray it regularly in the evening when your bees have gone to bed. All biologicals work best if you use them before pests or disease take over the garden.
By far the best way to keep bad bugs & disease out of your garden is to STOP USING CHEMICALS in the first place, especially high nitrogen fertilizers. Organic farmers know this. In plants, just as with humans, STRESS is a primary cause of disease. Here is how to grow strong, happy plants: Aerate your soil, add organic matter, neutralize soil pH, stick with organic fertilizers that break down slowly, provide the proper amount of sun or shade and water, choose disease resistant varieties of plants, plant them at the proper depth, and use a thin layer of mulch. (Need details? There is more than I have time to write here. Come to class!) Planting more native plants like Goldenrod and Joe Pye Weed will help bring more good guys into your garden to out-number the bad.
Things to do now:
Make a list of what you are planting next. Start preparing the soil now. Order your vegetable & flower seeds. Start lettuce seeds inside in mid February. (Costco has inexpensive row cover fabric to protect your early plantings from frost.) Don’t start your tomato & pepper seeds inside until late March or they will out-grow your space inside. Fertilize seedlings with a diluted fish & seaweed emulsion. (That blue stuff can burn their tender roots.)
Happy Gardening! Only 85 days until spring!