from R&D Innovator Volume 1, Number 3
From Patio to Pesticide
by Robert O. Larson
Mr. Larson imports rare wood, mainly for musical instrument
construction. He also
conducts seminars on using neem extract for insect control in the
field and stored grain.
I was skimming the Atlanta
Journal, killing time before my next flight, when I spotted an article on a
U. S. Department of Agriculture research group that formulated a
pesticide from an extract of the neem seed kernel.
A flood of memories rushed over me as I recalled visiting
V.R. Sonti in Nagpur, India in 1973.
My host and I were having a night-cap on his veranda when I
noticed the bizarre absence of insects.
This is how I reconstruct our conversation:
"Teddy, how come that even with these bright fluorescent
bulbs, I see no bugs?"
"I think it has something to do with those two neem trees in
"What's a neem tree?"
"It's in the mahogany family."
"Okay, but what does it do?"
"They say when the breeze blows through the neem tree, the
air takes on an odor that flying insects dislike.
They stay upwind of the smell."
I walked over to a tree; it seemed odorless. But when I chewed a
leaf, I spat it out hastily -- it was extremely bitter.
We continued talking.
"What else can you tell me?"
"My wife washes and dries the seeds, then puts them in with
our food grains."
"So what happens?"
"No bugs get into our food bins."
"Really? What else?"
"Well, she takes fresh leaves and puts them under our
mattresses and then bugs don't crawl up into our beds."
As we continued talking, the wonders of this tree began to take on
mythical dimensions. His wife, it turned out, put leaves in books to keep insects
from devouring them and put leaves in woolens to deter moths from
"Sure. If you crush the leaves and rub them on your body,
mosquitoes won't bite."
He went on to say that neem leaf juice would cure scabies, relieve
rashes, and prevent scarring from poxes.
He closed his fascinating lesson by mentioning that neem
twig toothbrushes reduce cavities and prevent gum disease.
I was hooked, but I'm a hardwood importer, not a botanical
pesticide expert. What
could I do with the information?
Something else was bothering me.
Even though several hundred million Indians were using this
tree every day, we in the West hadn't heard much about it. I asked why not.
"No money in it, I guess."
In the Atlanta airport, I felt my amazement return after all those
years, so I phoned the USDA researcher named in the article.
When I told Martin Jacobson what I knew, he invited me to
visit his lab in Beltsville, Maryland.
There, the chemists and entomologists of the "Neem
Team" reviewed their remarkable insect control results and
asked me to obtain better seeds. When I proved able to do that, they were apparently
impressed; at any rate, they invited me to help them produce a
stable pesticide from the neem tree.
The neem team suspected that the active ingredient in deterring
and killing insects was a recently isolated molecule named
I learned that big chemical companies were not
interested in working with an unpatentable, natural product.
The molecule was complex and incompletely understood; no
one believed such a tetranortriterpenoid molecule could be
synthesized at the time.
I was intrigued and flattered by the challenge and the team's
request for help. Despite
a smattering of biology and zoology in my background, I'm no
chemist. I decided my
best contributions would be my abundant curiosity,
resourcefulness, and tenacity.
I drew up an accord with USDA stipulating that I would
oversee the development of an effective and stable pesticide and
they, together with USDA researchers nationwide, would study its
efficacy on insects and plants.
At first, I couldn't find a chemist able and willing to work in
this eclectic area, but I reasoned that since azadirachtin was
plant-derived, food chemists might be interested.
I located a chemistry lab with a rich background in
consulting to agriculture and food companies.
Early on, we recognized that the chief problem was not
making an effective extract, but in stabilizing it.
Because the USDA extract decomposed by 75 percent in just
four weeks, it was commercially useless. We determined that
azadirachtin was most stable in acid conditions. That made eminent good sense, since its home in the seed was
acidic as well. When
we held the pH between 3.8 and 4, like in the seed, the product
held stable for months at a time.
Refrigeration enhanced stability but brought about oil
separation upon prolonged storage, and this made it difficult to
dilute the material with water for spraying plants.
It occurred to me that freezing the extract might cause the
oil(s) to separate and the problem oil(s) could then be removed,
permitting the easily emulsifiable oils which contained the active
material. This worked
beautifully on the first trial and the revised formulation was the
one submitted for registration by the Environmental Protection
We named the product Margosan-O after margosa, the Portugese name
for neem. My first
seeds came from a pharmacist who'd been raised in the former
Portugese colony of Goa and labelled the package "Margosa."
The USDA lab tests showed that Margosan-O diluted with
water was death, delay and heartbreak to insects.
Even dilute extracts gave up to 30 days activity before
decomposing into benign chemicals.
was shown to be non-toxic to mammals, and extremely
"soft" on good predator insects.
It is harmless, for example, to honeybees, beneficial
wasps, butterflies, and ladybugs.
These results indicate that this pesticide has a unique
ability to control more than 135 insects such as whiteflies, gypsy
moths, leafminers and thrips without harming the environment.
Earthworms, actually increased in number after Margosan-O
spray ran off into the soil!
This highly selective pesticide received a U.S. patent and
was registered for use on non-food crops in 1986.
Lately, Neem has been receiving quite a bit of attention worldwide
as various corporations and agricultural entitities learn
about the many uses of neem—from pesticides derived from a seed
extract to hygienic and medicinal products from other parts of the
tree. Truly a tree
for the 90's...and beyond!
What do I conclude from this serendipitous history?
The development of Margosan-O was stimulated from just
about every imaginable source.
A news article in Atlanta freshened a memory of an evening
in India, which led me to visit the USDA in Maryland, where I
became obsessed by this natural product.
The use of food chemists on a pesticide problem helped
overcome a shortage of the "right" technical expertise.
Many other people read the Atlanta
Journal, many others have visited India, and others knew of
the USDA research on neem. My
interests in exotic wood and the environment were the catalysts
that stimulated me to evolve an idea into a useful product.
I take no great personal pride in the development of Margosan-O;
My own contributions were embarrassingly minimal.
I served more as a conduit for the knowledge and efforts of
others than as an laboratory-man.
Perhaps that defines the ideal role of the entrepreneur.