Survey of Citrus Nematode Tylenchulus semipenetrans Causing Citrus Slow Decline in Karbala Province of Iraq

Jabbar, W.J.A. and E.M. Abedulridah. 2023. Survey of Citrus Nematode Tylenchulus semipenetrans Causing Citrus Slow Decline in Karbala Province of Iraq. Arab Journal of Plant Protection, 41(1): 8-11. https://doi.org/10.22268/AJPP-41.1.008011 The study aimed to determine the rate and severity of infection with citrus nematodes associated with the citrus slow decline in orchards and nurseries in different regions of Karbala governorate, including Aoun, Hay Al-Amel, Al-Haidariat, Al-Hurr Al-Saghir, Al-Bubiyat, AlHussainiya, and Al-Hindiya. The nematodes associated with citrus slow decline were isolated and phenotypically diagnosed based on microscopic examination of the infected stained roots, and juveniles in the soil based on the phenotypic characteristics of the citrus nematodes. Infestation rate in citrus orchards was assessed, and the severity of infestation was determined based on the number of females in 2 gm roots and the number of juveniles in 100 gm of the rhizospheric soil surrounding the roots. The causes of infection dissemination and the factors that contribute to the increase of infection in the severely affected orchards were investigated. The results of the field survey showed the presence of citrus nematodes infestation in all orchards and in all regions. The incidence and severity of citrus nematode infection differed between the different sites. It was found that the severity of infection was significantly higher with older trees compared to newly established orchards with young plants. The results of the questionnaire accompanying the field survey showed that most citrus orchards were not subject to nematode control practices. In addition, most farmers were not aware of the importance of plant parasitic nematodes and the damage they can cause, especially citrus nematodes. Keywords: Citrus nematode, Tylenchulus semipenetrans, survey, Iraq