Abstract:Cotton aphid, Aphis gossypii Glover is one of the main pest of cotton, cucurits and some other crop plants. But the capacity of the aphids to use those host plants is different, some host biotypes were found in many countries or regions. The fitness of two host biotypes of cotton aphid, cotton and cucumber biotypes, screened in our laboratory was studied. The survival, reproduction and EAG response of the cotton and cucumber biotype aphid to eight summer host plants were measured by host transplantation met...