X-ray doses to safely release the parasitoid Diachasmimorpha longicaudata (Hymenoptera: Braconidae) reared on Anastrepha fraterculus larvae (Diptera: Tephritidae)

G.E. BACHMANN; L.Z. CARABAJAL PALADINO; C.A. CONTE; F. DEVESCOVI; F.H. MILLA; J.L. CLADERA; D.F. SEGURA; M.M. VISCARRET

BIOCONTROL SCIENCE AND TECHNOLOGY

TAYLOR & FRANCIS LTD

Lugar: Londres; Año: 2015 vol. 25 p. 1092 - 1103

0958-3157

Diachasmimorpha longicaudata is a koinobiont larval parasitoid that is currentlyused to control fruit flies of the genera Anastrepha, Ceratitis and Bactrocera. Inthe rearing process, a fraction of the host larvae that are exposed to parasitoidsescape from parasitism and develop into viable and fertile flies. This creates the20 need to eliminate emerging flies before the parasitoids are shipped for release,increasing costs due to additional handling steps. Exposure of fly eggs or larvae togamma-irradiation before they are parasitised has been used to reproductivelysterilise hosts, or even inhibit their emergence. Our aim was to determine whetherX-ray radiation applied to Anastrepha fraterculus third instar larvae before they25 are exposed to parasitoids, inhibits fly emergence in non-parasitised larvaewithout affecting the performance of the parasitoids that emerge from parasitisedlarvae. Three X-ray doses: 6250.2 R, 8333.6 R and 10417 R (equivalent to 60, 80and 100 Gy, respectively) and one γ-ray dose (100 Gy) were tested. Fly emergencedecreased with increasing doses of radiation, showing null values for the higher30 X-ray dose and the dose of 100 Gy. Irradiation showed either no impact or apositive effect on parasitism rate and fecundity. Sex rate was biased towardsfemales in almost every dose. We conclude that the two types of radiationevaluated here were equally effective in suppressing fly emergence with nodetrimental effects on the biological quality of the produced parasitoids. X-rays35 offer an alternative method of irradiation than the conventional radiation source,i.e. γ-rays. These results represent a significant improvement in the development of a biological control programme against A. fraterculus.