The Government of Thail and, through its Department of Agriculture based at Chatuchak, Bangkok, has requested the assistance of the International Institute of Tropical Agriculture (IITA) to help in the biological control of the cassava mealybug, Phenacoccus manihoti, which had recently invaded country and possibly also Laos and Cambodia.
The mealybug has already spread over 160,000 hectares around the East and Northeastern provinces of Thail and, where cassava is an important export crop mainly for starch production and cattle feed.
To halt the spread of the mealy bug, a stock rearing colony of Anagyrus lopezi, a natural enemy of the pest, has been imported into Thail and from the IITA laboratories in Benin by Georg Goergen, IITA Entomologist. Goergen brought the materials in September 2009.
The wasps were placed into rearing under quarantine conditions in Bangkok and released in November 2009 after release permits were issued. Further releases were made in January 2010.
It will be recalled that this same mealybug had reached Africa in the late 1970s and caused widespread devastation and even famine when it destroyed cassava, which in Africa is an important food and locally traded subsistence crop.
Respite came when an IITA-led group of institutions initiated a campaign to find, import, rear and distribute adapted natural enemies from South America, the purported home of the foreign invader. By 1981, the encyrtid parasitoid A. lopezi (then Apoanagyrus or Epidinocarsis) was located in Paraguay, later in Brazil, shipped through quarantine, mass-reared at IITA and distributed. What followed was one of the greatest recent successes in classical biological control.
In Thail and, the cassava mealybug was not immediately recognized because another closely related mealybug species common on cassava, presumably Phenacoccus madeirensis, confused the situation, according to Peter Neuenschw ander, IITA Emeritus Scientist based in IITA-Benin. He says the identification of the mealybug by a taxonomic authority cleared the path for classical biological control.
It is hoped that IITA’s involvement in the mealybug control project in Asia will produce results within a much shorter time span and at much reduced costs as experts intend to leverage on past experience and techniques that made the African success story.
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For more information, please contact:
Dr. Peter Neuenschw ander, p.neuenschw ander@cgiar.org
Scientist Emeritus
IITA-Benin
Dr. Georg Goergen, g.goergen@cgiar.org
Entomologist
IITA-Benin
Godwin Atser, g.atser@cgiar.org
Corporate Communications Officer (West Africa)
Jeffrey T. Oliver, o.jeffrey@cgiar.org
Corporate Communications Officer (International)
Communication Office
IITA – Headquarters
Ibadan, Nigeria
About IITA
Africa has complex problems that plague agriculture and people’s lives. We develop agricultural solutions with our partners to tackle hunger and poverty. Our award winning research for development (R4D) is based on focused, authoritative thinking anchored on the development needs of sub-Saharan Africa. We work with partners in Africa and beyond to reduce producer and consumer risks, enhance crop quality and productivity, and generate wealth from agriculture. IITA is an international non-profit R4D organization established in 1967, governed by a Board of Trustees, and supported primarily by the CGIAR.
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