T. Mastrangelo,1,2 A. G. Parker,3 A. Jessup,3 R. Pereira,4 D. Orozco-Dávila,3 A. Islam,3 T. Dammalage,3 and J.M.M. Walder1

1 Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, Avenida Centenário 303, Caixa Postal 96, 13400-970 Piracicaba, SP, Brazil.

3 Entomology Unit, FAO/IAEA Agriculture and Biotechnology Laboratory, A-2444 Seibersdorf, Austria.

4 Insect Pest Control Section, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Wagrammer Strasse 5, A-1400 Vienna, Austria.

2 Corresponding author, e-mail: piaui@cena.usp.br.


Recent fears of terrorism have provoked an increase in delays and denials of transboundary shipments of radioisotopes. This represents a serious constraint to sterile insect technique (SIT) programs around the world as they rely on the use of ionizing radiation from radioisotopes for insect sterilization. To validate a novel X ray irradiator, a series of studies onCeratitis capitata (Wiedemann) and Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae) were carried out, comparing the relative biological effectiveness (RBE) between X rays and traditional γ radiation from 60Co. Male C. capitata pupae and pupae of both sexes of A. fraterculus, both 24–48 h before adult emergence, were irradiated with doses ranging from 15 to 120 Gy and 10–70 Gy, respectively. Estimated mean doses of 91.2 Gy of X and 124.9 Gy of γ radiation induced 99% sterility in C. capitata males. Irradiated A. fraterculus were 99% sterile at ≈40 – 60 Gy for both radiation treatments. Standard quality control parameters and mating indices were not significantly affected by the two types of radiation. The RBE did not differ significantly between the tested X and γ radiation, and X rays are as biologically effective for SIT purposes as γ rays are. This work confirms the suitability of this new generation of X ray irradiators for pest control programs that integrate the SIT.

Received: April 29, 2009; Accepted:October 21, 2009

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