Effects of photoactivable molecules during immature stages of dipterans

RABOSSI ET AL (QUESADA ALLUE, L.A.)

Salvador-Bahia-Brazil

Simposio; 7th International Symposium on fruit flies of economic importance y otro; 2006

IAEA-Agencia Internacional de Energfía Atómica

  Topic: Biocontrol & other control methods EFFECTS OF PHOTOACTIVABLE MOLECULES DURING IMMATURE STAGES OF DIPTERANS Alejandro Rabossi (Bioquimica y Biol. Mol. del desarrollo (FCEyN-UBA, IIBBA-CONICET and Fund. Inst Leloir)), Luciana Pujol-lereis (Bioquimica y Biol. Mol. del desarrollo (FCEyN-UBA, IIBBA-CONICET and Fund. Inst Leloir)), Adrian Filiberti (Dpto Quimica Biol. UNC,CIQUIBIC-CONICET), Carlos E. Argarana (Dpto Quimica Biol. UNC,CIQUIBIC-CONICET), Luis A. Quesada-allué (Bioquimica y Biol. Mol. del desarrollo (FCEyN-UBA, IIBBA-CONICET and Fund. Inst Leloir)) Abstract We previously demonstrated (Berni et al, 2003) the chemical and photochemical toxicity of Phloxin B (PhB) (a red xanthene eosin) on immature stages of the Medfly, Ceratitis capitata. This dye represents an interesting option to traditional insecticides. In an attempt to enhance the efficacy of PhB, uranine, fluorescein-di-acetate, and several surfactants were analyzed alone and mixed whit PHB 0.5 mM. Only uranine and tergitol 0.1 % increased slightly jumping larvae mortality when exposed to light. Hematoporphyrin (HP) and the lactone Santonin, were also analized. Hematoporphyrin was aproximately 3 times more toxic than PhB (LC50: 0.143 mM). Both, PhB and HP generated macroscopic abnormalities during development, apparently related to longitudinal muscles damage, as deduced from elongation of puparia and abortive ecdysis. Abnormal adults were also observed. Santonin did not produced significant mortality when added to food. However, an important extension of larvae III stage was registered at 1 and 1.5 mM. A special set of devices and conditions have to be implemented for growing Haematobia irritans (the horn fly). We have been able to establish cultures using cattle dung extracts, that allowed normal development from egg to adult. However conditions for mating in artificial conditions were not attained yet. We have demonstrate the following: (1) Chemical toxicity of PhB: At 0.5 mM PhB, mortality of Horn fly was 73,3%, thus showing very high sensitivity to the dye. (2) After exposition to light, photochemical toxicity was much higher, at much lower concentrations. (100% death after 90 min exposure to light with 0.1 mM PhB. Moreover, 96,8% death was attained for Musca domestica after 8 hours exposure to light with 5 mM PhB ).