Parasitization of maize by Heterodera avenae and H. filipjevi

Abstract

Fewer second stage juveniles of Heterodera avenae and H. filipjevi penetrate the roots of winter maize than penetrate wheat roots. The majority of the penetrated juveniles develop to adulthood in primary roots but females remain small, trapped inside the roots, and are unable to reproduce. Developing males mostly remain inside the roots in February-sown plants but emerge into the soil in December-sown plants. The adult stage of both nematode species is reached in about 5 weeks in February-sown and in 8-9 weeks in December-sown plants of wheat as well as maize. Some of the second stage juveniles entering the stelar region in February-sown plants are surrounded by necrotic root tissues and fail to develop beyond this stage. Maize roots penetrated by H. avenae become hard and stubby; H. filipjevi infected roots become swollen, develop lateral branches but continue to grow. Winter maize can be exploited as a trap crop for the management of H. avenae and H. filipjevi.