-

Populations of the peach aphid heterozygous for a translocation between autosornes 1 and 3 were first discovered in Great Britain.
The inefectiveness of organophosphorus insecticides on peach aphids was observed in green houses of faculty of agriculture, Kara] in 1976. Cytological studies was carr ed out in 1981 to indicate that the translocation of peach aphid chromosomes in Iran and the relation between translocation and resistance to organophosphorus insecticides.
Some greenhouse reared clones and also clones reared from parthenogenetic female were used and tested for their resistance to 1ppm and 5ppm Diazinon, with four replications. Fourth instar apterous viviparae were disected in fixative. The smallest embryos were squashed on a slide under a cover slip. Slides were studied under phase contrast microscope. Those clones which showed resistance, had translocation in their autosome 1 and 3.