Control of cereal cyst nematodes in wheat

Wheat, maize and rice occupy the most eminent position among grain crops in terms of production, acreage and source of nutrition. Heterodera avenae, H. filipjevi and H. latipons are among the most important species of cereal cyst nematodes (CCN). Significant economic losses due to these nematodes have been reported from West Asia, North Africa, Europe, Australia and the United States. The yield losses due to CCN are estimated on wheat at 57%, 40%–92%, 8%–50% and 35% in Syria, Saudi Arabia, Australia, Oregon state respectively. The high yield loss is most likely related to the monoculture system and the fact that farmers are unaware of the presence of plant-parasitic nematodes in their fields or the existence of resistant varieties. We report the establishment of an accurate and easily applicable molecular tool to identify (PCR) and quantify (qPCR) the three Heterodera species. Once the presence of CCN in the field is established, the use of host resistance is considered the most cost efficient, environmentally friendly and accessible nematode management option. To date, eleven single dominant genes for resistance to various species and pathotypes of CCN have been reported. The two genes Cre1 and Cre3, conferring resistance against Heterodera avenae Ha13, were both successfully used in Australia and with a limited success within the CIMMYT international spring wheat improvement program. Other integrated control management options should be combined with genetic resistance in wheat including the use of non-hosts in the rotation (e.g. legumes) and other management practices (e.g. solarization).