03 April 2014

Organic Pesticides

The alarm bells have been ringing for several years about the decline of butterflies, bees and the other pollinators that provide food for the world. Without pollination there are few grains for animals, and no pollinated flowers for the production of fruits, herbs and vegetables.


As spring gardens are getting started, the timing was perfect for Barry Fugatt, Director of Tulsa Garden Center, to bring Dr. Raymond Cloyd from Kansas State University to fill us in on the latest research. Cloyd is a professor of entomology who has spent decades studying the benefits, harm and uselessness of various products that are labeled organic pesticides. 


Cloyd said there is lots of misinformation out there about organics since there is no such thing as an organic pesticide. There are selective pesticides made of materials found in nature but most of them either cause harm to beneficial insects, birds and fish or are a waste of your money.

“The problem is that people want insects dead,” said Cloyd. “Most gardeners want the most lethal chemicals available and when they go to the garden centers they cannot know what all those bottles are.”

Throughout his entertaining and information-packed talk to 100 Master Gardeners, Cloyd emphasized that natural and organic are not the same.

“Organic is a system of growing without toxic and chemical pesticides or fertilizers,” Cloyd said. “Organic gardening products that consumers see in advertising and stores imply that they are safer and they are not.”

Gardening products found in stores may be identified with the letters OMRI (www.omri.org) which stands for the Organic Materials Review Institute. That certification indicates that the product can be used on food in an organic garden but it does not indicate that the product is harmless.

“Always use the least toxic method or combination of methods that regulate or suppress the pests,” Cloyd said. “In particular, avoid conventional pesticides that kill everything, such as Organophosphates (Malathion and acephate or Orthene), Neonictonoids (broad spectrum nicotine pesticides such as Imidacloprid or Merit), and Carbamates (such as Carbaryl or Sevin)”.

It is best to identify the insect that is causing the problem and apply a selective product such as Neem Oil (BioNeem or Azadirachtin), Pyrethrins (Piperony plus Butoxide), Bacillus thuringensis (BT worm killer or Dipel), Rotenone, Spinosad, or Linalool (Linalool is toxic to aquatic life).

While BT works well to kill cabbage caterpillars, it also kills butterfly caterpillars that eat the treated leaves. BT can also be effective against mosquitoes and fungus gnats.

Select insecticidal soaps and horticultural or petroleum based oils over any other products to maximize safety to the environment, helpful insects, pets, wildlife and humans.

Products that are sold for insect control that are generally considered to be a waste of money include: Diatomaceous Earth, essential oils in various combinations, garlic, citrus, etc.

Use Dipel and Spinosad for small bagworms. Use insecticidal oil or soap for squash bug eggs and nymphs. Rosemary oil will kill spider mites but so will a hard spray of water from the hose. Thyme oil is marginally effective. Sulphur is an excellent miticide and cure for powdery mildew.

“The key is to use the least toxic methods available to reduce pests without significantly disrupting the ecosystem or environment while protecting plants,” Cloyd said. “Maximize the effects of less harmful methods by applying them when larva and adults are present, thoroughly covering of every inch of the plant, and, by applying at the frequency recommended on the label.”

The lower-impact methods kill fewer bees, earthworms, lady beetles, lacewings, birds, fish, and frogs while non-selective methods kill everything that contacts them.


One of Dr. Cloyd’s lectures is on YouTube at http://bit.ly/1pAgzMV. Pesticide information http://bit.ly/1lpiXJ9. Pollination video http://bit.ly/1ek0Mjf

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