Root-lesion nematode, Pratylenchus coffeae, (Zimmermann, 1898) Filipjev & Schuurmans Stekhoven, 1941, is a serious nematode pest in a number of agronomic and industrial crops. Soybean (Glycine max L.) is one of the most economically important cultivated crops in China and P. coffeae has only been reported on soybean in Zhejiang Province of China (Wei et al. 2013). In September 2017, five root and soil samples were collected in a soybean field, near Ningling county of Shangqiu City, Henan Province, China, two weeks before soybean (Shangdou No.6) harvest. The plants were growing poorly and had chlorotic leaves. Root-lesion nematodes were extracted using the modified Baermann funnel method for two days (Hooper et al. 2005). The average root-lesion nematode populations in soil were 575 nematodes/kg and in fresh roots 34 nematodes/g. The nematodes extracted from the roots were sterilized with 0.3% streptomycin sulfate and cultured on carrot disks at 25°C in the dark for propagation. Afterwards, eight soybean (...

Pratylenchus coffeae Filipjev & Schuurmans Stekhoven, 1941, is one of the most important root-lesion nematodes (RLN) parasitizing many agronomic and industrial crops (Wang et al. 2021). Corn (Zea m...

Background: The nematodes of the genus Helicotylenchus are root parasites of a wide variety of plants, and certain species can cause serious damage to their hosts. During a survey of the plant-parasitic nematode associated with tomato, a population of Helicotylenchus was collected from tomato roots and soil samples. Thus, one of the objectives of the study was to confirm the specie of Helicotylenchus obtained from the tomato samples based on morphological and molecular characteristics. In addition, a mass pure culture of plant-parasitic nematodes is key to pathogenicity studies and many other biological studies. However, a successful mass rearing method for Helicotylenchus has not been reported. Thus, the other objective of the study was to establish a method of culturing Helicotylenchus. Results: Based on both the morphological characteristics and molecular analysis of the internal transcribed spacer (ITS) and D2-D3 expansion region of 28S ribosomal RNA (rRNA) sequences the specimens were identified as Helicotylenchus microlobus. Phylogenetic analysis with the rRNA sequences of the ITS and 28S D2-D3 regions was consistent with molecular identification, suggesting this population formed a highly supported clade with other H. microlobus populations. Additionally, a method for culture of H. microlobus on carrot disks was established, and the effect of temperature on the reproduction rate (Rr) of H. microlobus was investigated. The optimum temperature for culturing H. microlobus on carrot disks was 27.5 °C and, after inoculation with 30 females of H. microlobus at 27.5 °C for 90 days, Rr reached 406. Conclusions: To our knowledge, this is the first detailed description of H. microlobus from tomato in China. This study also demonstrated that the carrot disk method is suitable for the culture of H. microlobus. This study lays a foundation for other related research on H. microlobus, and has significance for the study of Helicotylenchus.

Summary: Root-lesion nematodes, Pratylenchus spp., are economically important pathogens because of their detrimental and economic impact on a wide range of crops. In August 2018, two samples of both roots and rhizosphere soil were collected from a corn field in Liangyuanqu of Shangqiu city, Henan Province, China. Root-lesion nematodes were recovered from the roots and soil samples using the modified Baermann funnel extraction method. Both the morphological characters and molecular analysis of the internal transcribed spacer (ITS) and D2-D3 expansion region of 28S ribosomal RNA sequences confirmed that the root-lesion nematode population collected from corn in this study was P. neglectus. Phylogenetic analyses showed that this isolate formed a highly supported clade with other P. neglectus isolates. To the best of our knowledge, this is the first report of P. neglectus on corn in Henan Province of China. This study reports the first partial sequences of 28S D2-D3 region of P. neglectus on corn in China. Due to the great harmfulness of root-lesion nematodes to corn, care should be taken to prevent the spread of P. neglectus to other regions in China. At the same time, further study on the biological characteristics of P. neglectus is needed, which will be helpful to develop corresponding management and control strategies.

Wheat (Triticum aestivum L.) is the predominant grain crop and plays a pivotal role in grain production in Xinjiang Uygur Autonomous Region (XUAR), China. Its cultivated area constitutes approximat...