REN Haohao, MIAO Pu, LI Rongchao, ZHENG Qian, LIU Xiaokai, ZHOU Yang, JIANG Shijun, WANG Hui, CUI Jiangkuan
To clarify the distribution of tobacco root-knot nematode in the Huang-Huai tobacco growing region, a comprehensive survey was conducted from 2018 to 2023. The study covered 120 tobacco-growing areas across 12 key cities in four provinces within the Huang-Huai tobacco-growing region of China. The nematode species were identified using combination of morphological and molecular biology methods. The results indicated that widespread distribution of root-knot nematodes in the Huang-Huai tobacco region, with Meloidogyne incognita being the predominant species in the southern region. Additionally, M. arenaria, M. hapla and M. javanica were found in some local areas, albeit on a small scale. Among the surveyed 120 tobacco-growing areas, M. incognita were detected in 109 areas (90.83% detection rate), M. arenaria in 32 areas (26.67%), M. hapla in 8 areas (6.67%), and M. javanica in 3 areas (2.50%). Notably, severe mixed population of M. incognita were observed in some areas, including 18 tobacco-growing regions with co-infection by M. incognita and M. arenaria (15.00%), 5 regions with co-infection by M. hapla(4.17%), and 3 regions with triple co-infections of M. incognita and M. arenaria (2.50%). Furthermore, the isolation and identification of second stage juveniles (J2s) of soil root knot nematodes revealed that the average highest concentration of J2s was found in tobacco fields soil from Pingdingshan, with 465.74 J2s per 100 mL of soil. The quantity of J2s in tobacco fields soil from Nanyang and Luoyang regions were 398.17 and 276.79 J2s per 100 mL soil, respectively. The study also found a significant correlation between severe infestations of tobacco root-knot nematode and the occurrence of root and stem fungal diseases, both of which were prevalent in these areas. The investigation provides a comprehensive understanding of the distribution of tobacco root-knot nematodes in the Huang-Huai tobacco growing region, highlighting their role as a major threat to tobacco production. The research results contribute valuable data to monitoring, early warning systems, and management strategies for controlling tobacco root-knot nematode disease in China. Finally, this study offers critical insights into the population dynamics of Meloidogyne species in the country, establishing a strong theoretical and empirical foundation for future research and pest management strategies.
