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Practical
Lifestyle
REVIVING
THE DERRIS PRODUCTION INDUSTRY
Noel
F. de Jesus
The
rotenoids from plants like derris stand out for their potency and
effectiveness against many crop pests.
The
high cost of synthetic pesticides, the uncanny way that insects
have of becoming resistant to these poisons, and the growing concern
over environmental contamination by synthetic chemicals, have spurned
renewed interest in the production of botanical pesticides. These
are nature's pesticides-plants with root, stem, leaf, fruit or flower
extracts that some of our farmers have traditionally used to kill
destructive crop pests.
Scientists have already extracted "toxic" substances from
marigold, black pepper, garlic, tobacco and even weeds. One commercial
pesticide, pyrethrin, is made from chrysanthemum flowers.
Among
botanical pesticides, however, the rotenoids stand out for their
potency and effectiveness against many crop pests. They are as effective
as the pyrethrin and 15 times more toxic than the nicotine in tobacco.
The development of natural resistance or insect immunity to these
botanical pesticides have rarely been reported despite their widespread
and continued use since 1848.
Export
of Derris roots, the main source of rotenoids for pesticide formulations
in the United States, was a fledgling yet thriving industry in Southeast
Asia before World War II. The Philippines, Indonesia and Malaysia
were the major Derris suppliers before the war devastated the region's
plantations. The United States turned to South and Central America
for its Derris needs. In 1974, for instance, it imported 1.7 million
kilograms of roots.
While these countries remain the major suppliers of Derris roots
for the West's pesticide formulations, Southeast Asia has every
chance of competing in the growing lucrative market by reestablishing
its Derris plantations.
To
revitalize the Derris industry in the region, the breeding and widescale
planting of Derris with high levels of rotenoids must be supported
by the government's agricultural research agencies.
Uses
and advantages of Derris root extracts
With an ancient reputation, in Southeast Asia, it is popular as
a fish killer. It has been used to eliminate the deadly piranha
in Brazilian rivers. Today, it is used to kill predators like mudfish
and gourami or trash fish in fish and prawn ponds. It is sold under
brand names like Fishtox, Noxfish and Pronoxfish.
The
insecticidal properties of Derris roots were first discovered in
1848 and the plant was first used against the nutmeg caterpillar.
Derris was patented for use as an insecticide in England during
the late 19th century. American farmers started using it in 1911.
By 1940, the United States was importing 2,700 metric tons of Derris
roots mainly from Southeast Asia to formulate pesticides. In 1975,
it imported 1.7 million kilograms of Derris roots from South America
and Africa. The market can only expand because of the escalating
cost of synthetic pesticides and their ill-effects on the environment.
Today,
there are more than 50 Derris-based commercial pesticide formulations.
Most of these are used to kill insects and unwanted fish. These
include Rotenox 5 WP, Rotenone 5EC and Noxfire 5EC.
Applied
as a powder or spray, Derris is toxic to a wide range of insect
pests of human beings, domesticated animals, and agricultural crops.
It is very effective against aphids, beetles, borers, the diamondblack
moth, fruitflies, thrips, cabbage worms, fleas, fleabeetles, lice,
loopers, mites, mosquitoes, paylids, slugs, and others.
It
is recommended for bush and vine crops, citrus, deciduous fruits,
mushrooms, asparagus, beans, beets, corn, forage crops, peas, potato,
radish, strawberry and other vegetables.
Derris is popular as an insecticide because it is safe to human
while toxic to target pests. In fact, a farmer can spray Derris
root extracts on a salad vegetable like cabbage today and sell the
produce tomorrow without endangering the health of consumers.
Derris root extracts easily and rapidly detoxify in our gastric
juices and when exposed to the environment. Its control action lasts
for a week. Thus, it does not pollute the environment; nor does
it accumulate in the food chain like the persistent synthetic insecticides.
Despite
its widespread use for 140 years, reports of insect resistance or
the development of immunity to Derris is rare. This is in stark
contrast to the synthetic pyrethroids to which insects become resistant
after only two to three seasons of continued use.
A farmer can use extracts as dust or crude water extract without
using costly or complicated extraction procedures.
Corn,
tobacco and mango farmers, who keep backyard plantings of Derris,
simply dig out some Derris roots in their backyard, crush or grind
these in water, and then spray the crude extract against pests.
They usually mix or dilute a concentration of 50 to 100 grams of
fresh roots in 16 liters of water. The dilution rate at which the
pest control material is effective is one part of root extract to
100 parts of water.
The
Derris plant
While the lack of recent studies on Derris cultivation may be a
handicap, the abundance of Derris species and their relative hardiness
as "wild, undomesticated forest plants" are important
factors in efforts to revitalize the industry.
In the Philippines, 13 Derris species thrive in thickets along riverbanks
and streams or forests at low elevations from Luzon to Mindanao.
They are locally called tubli (Derris elliptica), upi (Derris philippinensis),
tuglon (Derris polyntha), malasaga (Derris scandens) and tubling
tatlong dahon (Derris trifoliata).
The
most popular species is Derris elliptica, a plant with high levels
of rotenoid. Derris philippinensis is native to the country but
is rarely used as a source of rotenoid. Derris polyntha is also
a promising species; it appears to be more toxic to mosquito larvae
than the first two species.
Derris
is a sturdy leafy leguminous vine. It has fast-growing, brown, hairy
branches that climb ramblingly on trellises and intertwine profusely
on the ground. They can fix nitrogen in symbiosis with native rhizobia,
making them covercrops to improve the fertility of newly established
tree plantations.
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