Plant-parasitic nematodes associated with sweet potato rhizosphere soil in the Semi- Deciduous Forest and Coastal Savannah Zones of Ghana

Abstract

A survey was conducted in nine major sweet potato producing districts across the semi-deciduous forest and coastal savannah zones of Ghana to determine the prevalence of plant-parasitic nematodes parasitizing the crop. Soil samples were collected at 90-days after planting from the rhizosphere of sweet potato crop and analysed using Modified Baermann tray method from 100 farms across the study area. Seven plant-parasitic nematode genera were extracted from soil samples collected and morphologically identified under a microscope with four of them, namely Meloidogyne, Pratylenchus, Rotylenchulus, and Helicotylenchus being the most prevalent. Scutellonema sp. occurred in 89% while Tylenchus sp. occurred in 33% of the districts sampled. The ring nematode, Criconemella sp. was found in only two of the nine districts covered; Ketu North and Akatsi South which incidentally recorded 100% of the seven nematodes encountered in the survey. The abundant nematode was Meloidogyne sp. which represented 39% and Criconemella, the least (0.1%) of the total nematodes recovered in the survey. This study has shown that high diversity, incidence and density of economically important plant-parasitic nematodes are associated with sweet potato crop. Development of appropriate management strategies to mitigate the negative effects of plant-parasitic nematodes on sweet potato is recommended.