The author studies a nonautonomous single species Kolmogorov system with delays of the type
where This equation includes many special delayed nonautonomous population growth models of a single species. The results obtained in this paper extend the main results given by R. R. Vance and E. A. Coddington [J. Math. Biol. 27, 491–506 (1989; Zbl 0716.92016)], establishing in particular different general criteria on the boundedness, persistence, permanence, global asymptotic stability and the existence of positive periodic solutions for the equation above.