Influence of temperature and storage conditions on the hatching behavior of cereal cyst nematodes (Heterodera avenae Wollenweber) from Egypt

The cereal cyst nematode Heterodera avenae has been reported in wheat fields in Egypt; however no information is available on the hatch of second-stage juveniles (J2) from such populations of H. avenae. The aim of this study was to subject five Egyptian populations of H. avenae that were obtained from different regions in the Ismailia Province to different temperatures and storage durations to determine the effects on J2 emergence. The Egyptian populations of H. avenae were compared to a population originating from a different climatic zone in Germany (Grafenreuth, Bavaria). Results showed that the J2 hatching pattern of the Egyptian H. avenae populations did not differ from each other. Although the Egyptian and the German populations of H. avenae hatched primarily between 5 and 20 °C, significant differences in J2 hatching have been observed among them. Highest emergence of J2 of the Egyptian populations was observed between 10 and 15 °C, whereas the highest level of J2 emergence of the German population was between 5 and 10 °C. Storing cysts to 5 °C before incubation at 10 °C stimulated the hatch of the German population of H. avenae significantly compared to the control. Whereas, storing cysts at 20 °C, before incubation at 10 °C, significantly stimulated J2 hatching of the Egyptian populations compared to the control. The J2 hatching behavior of the Egyptian populations of H. avenae was in agreement with reports for Mediterranean ecotypes which have winter activity, while the hatching pattern of the German population was similar to those of the Northern ecotypes with spring activity.