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Root-lesion nematodes of the genus Pratylenchus are among the most important nematode pests that limit production of small-grain cereals. Four Pratylenchus species, viz. P. thornei, P. neglectus, P. penetrans, and P. crenatus, are considered of major economic significance in cereals of which P. thornei and P. neglectus are the most important and widely distributed species in cereal crops worldwide. However, P. thornei is more destructive causing estimated yield losses of up to 50% in the USA and 85% in Australia. This paper provides information regarding the global distribution of Pratylenchus species, yield loss due to their attack, their biology and pathogenic relation to plants, the research cutting edges in nematode identification of different Pratylenchus species, and their control through cultural practices and resistant varieties as correct identification of root-lesion nematodes can be difficult to achieve, particularly if a quick diagnosis is needed. In this context, in recent years, several molecular techniques for these Pratylenchus species have been developed such as quantitative PCR assays which are able to produce precise and rapid identification of several root-lesion nematodes species. So far, many global attempts have been made to control root-lesion nematodes in cereals, including cultural practices and development of resistant varieties. The use of resistant accessions is considered the most economically feasible and environmentally sustainable method. Resistance genes in several lines have been identified and are being used in numerous breeding programmes against root-lesion nematodes species. [ABSTRACT FROM AUTHOR]

Cereal cyst nematodes (CCN) are important plant-parasitic nematodes of wheat and barley, and exist in most of the cereal growing regions of the world. As there is limited information on the nature and distribution of CCN species in Syria, a survey was conducted in north-eastern Syria to assess the distribution of CCN in the main wheat and barley growing areas. In the summer of 2009, a total of 167 composite soil samples were collected from 167 wheat and barley fields. Cysts were extracted from soil using the Fenwick can technique, then quantified and identified up to the species level by using both morphological and molecular methods. The study revealed that 62% of the fields were infested with the three Heterodera species: H. avenae, H. filipjevi and H. latipons. However, the most prevalent species was H. latipons, which was present in 76% of the infested samples, while it occurred alone in 67% of those samples. Heterodera avenae was detected singly in 20% of the samples, while 11% consisted of mixed populations with other species. Heterodera filipjevi was never detected alone; it was found mixed with H. avenae and/or H. latipons in 9% of the samples. The high number of extracted cysts (up to 116 cysts × 200 g-1 of soil) is most likely related to the monoculture practiced in that region and the fact that growers are unaware of the existence of resistant varieties. [ABSTRACT FROM AUTHOR]