Archive for herbicide

Alternatives to Toxic Insecticides

Alternatives to Toxic Insecticides

By George Giltner, Adv. Master Gardener, MS Biology

A third study now validates results of earlier research of associations between autism and prenatal exposure to agriculture chemicals (www.ehp.niehs.nih.gov/1307044/).  “Women who are pregnant should take care to avoid contact with agricultural chemicals whenever possible” says author, Janie F. Shelton who is now a consultant with the U.N.

Three groups of common pesticides were studied that included organophosphates (chlorpyrifos, acephate, diazinon, and others), pyrethroids (esfenvalerate, lambda-cypermethrin, taufluvalinate, and others), and carbamates (methomyl, carbaryl, and others). The organophosphates were associated with an elevated risk of autism spectrum disorder, especially chlorpyrifos applications in the second trimester. Pyrethroids had a moderate association with autism spectrum disorder immediately prior to conception and in the third trimester. Carbamates were associated with developmental delays.

The present rate of autism is now at 1:68 births according to estimates from the CDC.  Also about 1 in 6 children in the United States had a developmental disability in 2006-2008. In the birth year of 1992, the prevalence of Autism Spectrum Disorder was 1 in 150, which has steadily increased to 1 in 68 in the 2002 birth year.

Therefore as gardeners, we should always use the least toxic chemicals, read labels, follow all safety precautions, and keep up with the latest research concerning pest control.

The good news is that more and more information is available on less toxic pesticides.  Clemson Cooperative Extension has an outstanding article on “Less Toxic Insecticides” which conscientious gardeners should print out (www.clemson.edu/extension/hgic).  “Most essential oils used as pesticides work by disrupting an insect neurotransmitter that is not present in people, pets, or other vertebrates.” The EPA no longer requires approval for use as pesticides due to minimum risk to uses of these essential oils (cedar, cinnamon, citronella, citrus, clove, garlic, mints, rosemary and others).

Microbial insecticides include Bt (Bacillus thuringiensis) for caterpillar control.  Milky Spore (Bacillus papillae and lentimorbus) is used against June bug larvae – grub worms. Spinosad, Saccharopolyspora spinosa is a treatment for fire ants, caterpillars, thrips, whiteflies, aphids, and even borers of fruit trees. Beneficial nematodes are the good nematodes that control clearwing borers, cutworms, sod webworms, mole crickets, and grub worms.  However nematodes are difficult to get started due to humidity, moisture, shipping, and temperature issues.

Bacillus subtilis and pumilus combat downy and powdery mildews, rust, bacterial spot, blight, botrytis and multiple other mildews on veggies, fruits, ornamentals, trees, and shrubs.

Minerals like boric acid acts as a stomach poison which causes the insects to die from starvation.  Diatomaceous Earth controls slugs, millipedes, ants, cockroaches, and soft-bodied insects like aphids. However use the “natural grade”, not the swimming pool filtering-agent that poses an inhalation hazard.  Sodium Fluoaluminate has sharp edges which punctures insect (caterpillars, sawflies, beetles, etc.) gut cells from consuming leafy material, however beneficial insects are not affected since they are not leaf eaters.  Iron phosphate is used as an organic slug and snail bate.  It is not poisonous to cats and dogs.

“Organic Farm and Garden” 2013, Vol.1, 2nd Ed., lists Biological Control Options which incorporates predator and prey functions in every ecosystem.  Plant nectar sources attract beneficial insects, and allow them to lay eggs near this food source.  Plant small flower favorites like dill, parsley, fennel oregano, cilantro, and thyme.  Also include annuals like sunflowers, cosmos, amaranth, alyssum and statice.  Perennials like yarrow, tansy, daises and angelica can be inter-planted within your garden.  Your beautiful garden will buzz with beneficial insects, and will have an ecological balance of predator and prey bugs.

“Louisiana Gardener”, Feb. 2015, has a super article, “What’s Bugging You?” by Cindy Shapton.  She puts emphasis on learning good bugs and bad bugs. Numerous recipes for repellants to easy to make sticky-traps are highlighted.

“The Naturally Bug-free Garden”, 2012, by Anna Hess is now available at Amazon.  It focuses on the worst garden pests that we have here and in Texas, and gives organic control measures.  Good bugs and good animals are reviewed and used to make your garden a living balance of natural defenses.  Resistant varieties, row covers, companion planting, and plant nutrition are tools for helping plants resist insects.  This is a good book to assist the beginner and young gardeners in learning about organic gardening.  It is a treasure!

So this year, learn, read, and experiment with organic chemical-free gardening to avoid potentially dangerous chemicals that are used in commercial agriculture.

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Residue Problems with Herbicides in Gardening

Residue Problems with Herbicides in Gardening

By George Giltner, MS Biology, Adv. Master Gardener

 

A recent Mercola interview with MIT research scientist, Dr. Stephanie Seneff has raised the awareness of human health problems with glyphosate (Roundup) that has entered the American food supply by genetically modified organisms (GMO’s which include wheat, corn, soybeans, etc.).

 

Everyone has heard the sales pitch of how “biodegradable”, “environmentally friendly”, and “clean and inert” it is for years.  Now biochemical research is painting a different picture that looks more like an evil villain.  Mounting evidence according to Dr. Seneff pictures glyphosate as “the most important factor in the development of multiple chronic diseases and conditions that have become prevalent in Westernized societies”.

 

These chronic diseases are the result of nutritional deficiencies and systemic toxicity caused by glyphosate. Strangely, the mechanism of harm is through intestinal microbes.  Beneficial gut bacteria are preferentially affected (as weeds), causing disruption in microbial functions and lifecycle.  Pathogens flourish and then inflammation causes disease.  For a better description of the mechanisms, please view the hour-long interview: www.articles.mercola.com./sites/articles/archive/2013/06/09/monsanto-roundup-herbicide.aspx.  Note: Some terms are scientific, however concepts are simplified by an interviewer.  Discussions involve biochemical mechanisms related to autism, allergies, gastrointestinal diseases, diabetes, cardiovascular disease, etc.

 

When you do use Roundup at home treat it with respect. Wear PPE, bathe, wash clothes, and do not inhale spray droplets.  Keep the kids away from spray area and don’t let the dog roll in grass sprayed that will be rubbed off by petting at a later time.  Remember that the half life of glyphosate ranges from 1 to 174 days as water and bacterial action are required for degradation.  In ponds the half life is about 2 weeks to 10 weeks.

 

Another herbicide commonly used is “Sledgehammer”, halosulfuron-methyl. For controlling pesky nutgrass this herbicide will work by systemically destroying the nut tuber and stem.  The question always comes up – “Can I use it in my Vegetable Garden?”  The answer is emphatically “No” or “No Way”.  The reason – The EPA states that it can persist at toxic levels to plants for months or years.  Therefore if you have a garden area that was sprayed with this chemical, and it has not produced vegetables for years, it may be due this persistent chemical herbicide.

 

Yet another herbicide, Tordon (picloram) is commonly used to rid property of tallow trees or to destroy regrowth from stumps. The problem with Tordon is that it also persist for a long time, like several years.  Trees in the vicinity of a treated tree may also be killed as the chemical can be easily absorbed by nearby roots.  Broadleaf crops can be damage for up to two years.  Extension recommends use of Roundup for stumps and root sprouts.  Tordon should not be used for backyard usage.

 

These are just three examples of herbicides with residual or human health effects. Before you use any chemical for gardening, do like our county agent says, “Read everything on the herbicide label”.  Also be sure to wear PPE, and above all keep updated on new research and herbicide safety.

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Winter Burweed Should be Treated Before It’s Too Late

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Winter Burweed Should be Treated Before It is Too Late
Keith Hawkins, LSU AgCenter, Beauregard Parish

     As a County Agent for the AgCenter, I strive to help homeowners with their lawn question and provide the best research-based information available. However, in my own yard, my attitude towards turf is more lax. I mow the yard and treat for fire ants, and that was it as far as lawn maintenance was concerned. I regard my yard as more of a botanical collection and have learned to identify St. Augustine, Bermudagrass and bahia grass. My yard is also a training lab in learning lawn weeds such as annual bluegrass, henbit, dichondra, carpetweed, and other weeds.

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Lawn Burweed in the Winter. Image by LSU AgCenter

      I have been very tolerant of lawn weeds until I walked barefoot one spring a few years ago and encountered stickers. The stickers became so bad that Gracie, our female Maltese dog, would not walk on the yard. After attending Dr. Ron Strahan’s Master Gardener classes on turf and on weeds, I learned that I have lawn burweed, or stickerweed.

     When the stickers are felt, it is too late to treat. The trick to treating burweed is timing. I have already seen burweed in my yard this month of January so I will be treating soon to prevent the stickers.

     Last February I used an herbicide with the active ingredient call Atrazine and where I applied it in accordance with the label, the treatment was an overwhelming success. I did not treat the whole backyard, but there was enough burweed-free yard that Gracie could comfortably visit the lawn and conduct her business.

      One treatment worked well for me, but sometimes another treatment may be necessary. Here are the suggested products labeled to control lawn burweed:
o Atrazine 1.5 oz. / gal. water per 1000 sq. ft.
o Weed B Gone 3 oz. / gal water per 1000 sq. ft.
o Ferti Lome Weed Free Zone 1.5 oz./ gal. water per 1000 sq. ft.
o 2,4D 1.5 oz./gal. water per 1000 sq ft.
o Bayer Advanced Southern Weed killer 2 oz. /gal. water per 1000 sq ft.
o Trimec 2 oz. /gal. water per 1000 sq. ft.
o Spectracide Weedstop 2 2oz./gal. water per 1000 sq. ft.

     These products are safe to use as labeled. If you use these or any pesticides off-label then you can expect damage. Also, these products are labeled for turf and could harm broad-leaf plants such as ornamentals, trees and shrubs.

     The “take home” lesson for the homeowners is to find lawn burweed, a winter weed, early and treat it as soon as discovered. When you or your family feel the stickers, then it is too late to treat, and you will have to wait a year for the next chance to deal with this weed.

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