Resistance of Spring Wheats to the Wheat Stem Sawfly, <i>Cephus ductus</i> Nort. (Hymenoptera: Cephidae) II. Resistance to the Larva

Abstract

Wheats that are resistant to the wheat stem sawfly, Cephus cinctus Nort., differ in degree of resistance and in certain environments lose all or part of their resistance. The survival and behaviour of the larvae in different locations in the stems of various spring wheats have been examined with the object of determining some of the factors involved in resistance and in the variability of resistance. In the previous paper in this series (Holmes and Peterson, 1961) it was shown that resistance to hatching of the egg of the sawfly depended on the stem solidness of its host.