The life cycle of Heterodera filipjevi in winter wheat under microplot conditions in Iran
AbstractThe cereal cyst nematode, Heterodera filipjevi, is the dominant species in most wheat growing areas in Iran. Therefore, the life cycle of this nematode was studied on the winter wheat cv. Sardari in a microplot under rain-fed conditions for two years. The progress of the nematode development varied during the two years due to differences in seasonal temperatures and rainfall. In the soil, second-stage juveniles (J2s) were present from November through March. The penetration of J2s into the roots of wheat was observed in early December and late November in the first and second year, respectively, when the soil temperature at 10 cm depth was 10 °C and 10.4 °C. White females were visible on the roots in the first week of April and late March in first and second year, with soil temperatures of 13.3 °C and 12 °C, respectively. Cysts appeared one month after white females in both years. Heterodera filipjevi developed only one generation per growing season and completed its life-cycle within 155 (150±10) days in wheat. The development of white females and of embryonated eggs required an accumulation of 209 and 358 day degrees, respectively, above the basal developmental temperature of 8 °C.