A method of preparing moth specimens for strontium (Sr) analysis by atomic absorption spectrophotometry is described. A screenhouse experiment demonstrated that foliar sprays of SrCl2 at 5 kg/ha successfully marked late instar Heliothis armigera larvae feeding on chickpea. Laboratory experiments, in which larvae were reared from the 4th instar on artificial diet containing concentrations of SrCl2 up to 5000 ppm, showed no adverse effects on development and even at 50 ppm moths were unequivocally marked above the highest recorded background level. Sr levels did not decline appreciably after the second day of adult life, unlike rubidium which declined at a faster rate. Female moths had consistently higher Sr levels than males. Following a single field application of SrCl2 at 5 kg/ha on pigeonpea heavily infested with H. armigera larvae, 61.8% of emergent moths were marked.
Armes, N.J.; Carlaw, P.M.; Gadsen, H.; King, A.B.S. Evaluation of strontium as a trace-element marker for dispersal studies on Heliothis armigera. Entomologia Experimentalis et Applicata (1989) 51 (1) 5-10. [DOI: 10.1111/j.1570-7458.1989.tb01207.x]