Download Description of the sterile insect technique including a case study

Description of the sterile insect technique
including a case study
Siegrid Widhalm
24/01/2012
Applied Entomology in orchards, vineyards and horticultural crops 953.325
Definition
• Biologically‐based method for the management of insect pests
• „a method of pest control using area‐
wide inundative releases of steril insects to reduce reproduction in a field population of the same species“
• Sterile insects are not self‐replicating and therefore cannot become established in the environment
http://www.nature.com/nbt/journal/v23/n4/fig_tab/nbt0405‐
432_F1.html
History
• The entomologist E. Knipling
exploited H. Muller´s discovery that
ionizing radiation can induce
dominate lethal mutations
• This approach was first successfully
applied on the New World screw‐
worm fly Cochliomyia hominivorax in the USA, Mexico and Central America
(1957 – 1990)
• Currently, the SIT is most widely
applied against fruit flies.
http://en.wikipedia.org/wiki/File:EdwardF.KniplingEntomologist.jpg
Ionizing Radiation
• Cobalt‐60 is a synthetic radioactive isotope of cobalt
• Due to is half‐life of 5.27 years Co‐
60 is not found in nature
• Co‐60 decays to the stable isotope Ni‐60 by emitting two gamma rays
• When gamma radiation breaks DNA molecules, a cell may be able to repair the damaged genetic material but within limits
http://www.sciencephoto.com/media/210620/enlarge
Advantages and Success stories
• SIT does not introduce exotic species into an ecosystem
• Economies of scale by using a area‐wide pest management
• No use of pesticides and therefore no resistance????
• Direct benefits of screwworm fly eradication are estimated to be over $ 1.5 billion/ year, compared with a total investment of $ 1 billion
• Mexico protects a fruit and vegetable export market of over $ 3 billion/year through an annual investment of ca. $ 25 million
Drawback
• Radiation treatment can affect the health of the male
• The technique is species specific
• Standard operating procedures of mass rearing and irradiation do not leave room for mistakes
• SIT is a expensive method
• Radioactive source as a(potential) biohazard
Case study ‐ Moscamed • Mediterranean fruit fly Ceratitis capitata
• It is native to the Mediterranean area
• Appeared 1955 in Costa Rica, where it became established
• By 1977 had penetrated into southern Mexico
• In 1977 the United States, Mexico and Guatemala initiated Moscamed
• This program is designed to suppress Medfly populations and reduce the risk of introduction into the United States
Case study ‐ Moscamed Disinfection of the Mediterranean fruit fly eggs
Ceratitis capitata
Case study ‐ Moscamed 12 ml of eggs dispersed on 5kg diet
Optimal larvae maturation at 25°C and 80% humidity
Case study ‐ Moscamed Separation of larvae and diet
Pupation will start at 20°C, 60% humidity and darkness
Colouring for identification
Packing for irradiation
Case study ‐ Moscamed Radiation with 125 Gy, 40h before eclosion
Case study ‐ Moscamed Adult males are released by airplane
Approximately 500 million flies/week
References
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http://www‐naweb.iaea.org/nafa/ipc/biological‐control.html
http://en.wikipedia.org/wiki/Cobalt‐60
V.A. Dyck, J. Hendrichs and A.S. Robinson, Sterile Insect Technique. Principles and practice in area‐wide integrated pest management, Springer 2005
Vreysen, M.J.B.; Robinson, A.S.; Hendrichs, J. (Eds.), Area‐Wide Control of Insect Pests, 2007
http://www.iaea.org/newscenter/news/2011/battlingbugs.html
Radioisotopes and Ionizing Radiations in Entomology Vol. IV 1966‐1967, Bibliographical series No. 36. STI/PUB/21/36, IAEA, Vienna 1969
The New World Screwworm Eradication Programme. North Africa 1988‐1992, Food and Agriculture Organization of the United Nations, Rome, Italy 1992
Sterility Principle for Insect Control 1974 [pdf]. STI/PUB/377, IAEA, Vienna 1975
Thanks for your attention