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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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Spittle Bugs – the Mystery Foam Source

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Spittle Bugs – the Mystery Foam Source

By George Giltner, Master Gardener

two lined spittle bug

Two lined Spittle bug (Prosapia bicincta), Clemson University Coop Extension Service photos

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Spittle (bubbly froth mass with larvae), Clemson University Coop Extension Service photos

From the name, spittle, you know what to look for – a spit-looking mass on vegetation.  This frothy mass is excreted by yellow-brown nymphs mainly on grasses and ornamentals as defensive protection against predators and desiccation.  Below the froth, the nymphs insert piercing mouth parts into the plant consuming large amounts of plant juices.  They go through 4 instars before reaching adulthood.  Populations expand during wet humid climate periods and retract during drought.

In Louisiana, they can be found on grasses like St. Augustine, centipede, rye, Johnson, coastal Bermuda, and small grain crops.  Usually spittle bugs are not a problem, unless large populations develop under wet environmental conditions.  Pyrethroids can be used for control.  Also look for them in vines like honeysuckle and morning-glory and in ornamentals like holly, aster, and redbud where their feeding results in white blotches on the leaves.  They are most active in the morning to avoid the heat and drying conditions of hot afternoons.

The common two-lined spittle bug adults look like large black leafhoppers.  They are easily identified with two large red or orange stripes across their triangular-shaped body.  If you get close enough, notice the small red eyes.

The adults only live for three weeks, with females laying eggs during the last two weeks of their lives.  Eggs laid in the fall, overwinter in grass sheaths and ground debris.

The Pecan spittlebugs, Clastoptera achatina, are more of a problem insect, especially where pecans are grown.  The nymphs become active after bud break in the spring by feeding on young buds and later on tender shoots and nutlets.  Heavy populations can cause terminal bud death and immature nut shedding.  Infections can be recognized by white bubbly masses on terminal buds to dried yellowish masses on young nuts.  The adults are small, 4 to 5 mm, and yellowish brown in color.  Therefore they are hard to detect in pecan trees.

So the next time that you see those frothy masses on your plants, shrubs or trees, look for the larvae spittlebugs underneath.  At least you will know the source was not a rabid animal or from human origin.

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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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