NEWS: Neem Pesticide & Lecithin

Bob Batson bob at sky.net
Fri Nov 15 18:08:57 EST 1996


          Lecithin Inhibits Photodegradation of Neem Pesticide

  Azadirachtin, the potent insect repellent, antifeedant, and growth
regulator derived from seeds of the neem tree, is susceptible to rapid
breakdown in direct sunlight. But Canadian Forest Service workers have
discovered that lecithin -- yes, the lecithin found in health food
stores -- can greatly reduce photodegradation rates of azadirachtin,
thus extending the pesticide's period of high potency after it has been
sprayed on plant leaves. Lecithin boosted the half-life of azadirachtin
by more than ten-fold -- to about one week.
  The researchers only tested lecithin as a photodegradation inhibitor
for azadirachtin in methanol solutions; it isn't clear (to us) whether
simply adding some lecithin to a spray solution containing azadirachtin
would provide much benefit. We'll keep you informed as (we hope) this
technique becomes developed into a practical procedure for gardeners.
  Reference: K.M.S. Sundaram (Natural Resources Canada, Canadian Forest
Service, 1219 Queen Street East, P.O. Box 490, Sault Ste. Marie,
Ontario, CANADA P6A 5M7) and J. Curry, "Photostabilization of the
Botanical Insecticide Azadirachtin in the Presence of Lecithin as UV
Protectant," _Journal of Environmental Science and Health B: Pesticides,
Food Contaminants, and Agricultural Wastes_ 31(5), 1996, 1041-1060.
(Marcel Dekker, Inc., 270 Madison Ave., New York, NY 10016.)
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Reprinted with permission from the October 1996 _HortIdeas_. Copyright
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Bob Batson                              L 39 12 14 N  94 33 16 W
bob at sky.net                             Kansas City
TCS - Mystic Fire Priest                USDA zone 5b
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Under the most controlled conditions, the experimental apparatus will
do exactly as it pleases.
 



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