From: [email-masked] (David Dickerson)
Date: 23 Aug 93 05:22 PDT
Newsgroups: fido.econet

/* Written  4:26 pm  Aug 13, 1993 by ncamp in igc:en.pesticides */
/* ---------- "Cassava Field Protection" ---------- */
CIAT
International Center for Tropical Agriculture

                   Press Release

   A Homemade Pesticide Protects Cassava Fields

CALI, COLOMBIA - Farmers are using an environmentally friendly
pesticide to control the cassava hornworm in 34,000 hectares of
cassava in Brazil, say scientists at the International Center for
Tropical Agriculture (CIAT).

     "The pesticide - a spray containing a granulosis virus
disease that infects only the hornworm - could be used on 2 million hectares, "
Says Dr. Guy Henry, CIAT's cassava economist. "It can rid cassava fields of 60
to 100 percent of this major pest, and does no ecological damage."

     "This is significant," says Dr. Anthony Bellotti, CIAT's
cassava entomologist "because farmers use more chemical pesticides
for controlling the cassava hornworm than for any other cassava
pest."

     "Cassava, a tuberous root crop, feeds 500 million people.  As
a source of calories, it is the fourth most important crop in the
tropics, after rice, sugar, and maize, " Henry says.

     The hornworm virus disease was first studied and identified
by CIAT and the Boyce Thompson Institute of Cornell University,
USA.  It was developed as a pesticide by the Empresa de Pesquisa
Agropecuria de Santa Catarina (EMPASC), a Brazilian agricultural
research program, with funding from the Banco do Brasil.  EMPASC
provides the pesticide, frozen, to farmers.

     "But farmers can also make the pesticide themselves by
liquefying, in a kitchen blender, caterpillars that have died from
the virus," says Bellotti.  Twelve large caterpillars, mixed with
water, make enough spray to protect 1 hectare of cassava.
Infected caterpillars are easy to identify in the field: they are typically
balloon-shaped and readily burst, sending out a whitish, smelly liquid.

     The homemade pesticide does not contaminate the environment.
"Nor will it affect 'friendly' insects, which control other
cassava pests," Bellotti says.
     After eating cassava leaves contaminated with the virus,
young hornworms die within 2 to 3 days, and older, larger
caterpillars in 3 to 5 days.

     In Brazil, the caterpillars defoliate thousands of hectares
of young cassava, devouring leaves, buds, and young stems,
Bellotti explains.  Yields losses are about 20% to 30%, although,
with repeated attacks, they can reach 60%.  Brazilian cassava
farmers, mostly poor, can seldom afford pesticides.  Even if they
could, pesticides may worsen the problem by killing off the pest's
natural enemies, thus resulting in more frequent attacks. Because adult moths
are migratory, and strong fliers, outbreaks are sporadic and thus difficult to
control chemically.

     CIAT is dedicated to the alleviation of hunger and poverty in
developing countries of the tropics by applying science to
agriculture to increase production while sustaining the natural
resource base. CIAT is one of 18 international centers sponsored by the
Consultative Group on International Agricultural Research (CGIAR).

Contact:  Dr. Anthony Bellotti, Cassava Program; Dr.
  Thomas R. Hargrove, Communications Unit; CIAT.
  A.A. 6713 Cali, Colombia.  FAX 57-23-647243.  Tel.
  57-23-675050. IIT Dialcom ID 57:CG1301. Telex.  05769 CIAT CO.

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