Effect of soil factors on plant-parasitic nematode associated with tomato (Solanum lycopersicum), case study in Limpopo Province, South Africa

Abstract

Plant-parasitic nematodes are some of the most important plant pathogens in tomato farms. Tomato is an acritical and high-demand vegetable in the world. The plant-parasitic nematodes are highly adapted and can cause severe damage to tomato farms. Therefore, understanding the population of nematodes on the tomato field assists the farmer in managing them and having better yields. This study was conducted to identify nematode species from the soil and root samples during a survey of plant-parasitic nematodes in four tomato farms in 2021. The samples were collected across the farms in Limpopo province, South Africa. Analyzing the soil and identifying the nematodes has been done at the Aquaculture Research Unit, University of Limpopo. Seven nematode species were identified from the soil and root samples out of the 40 soil samples collected. The nematodes encountered were Meloidogyne (700), Pratylenchus (430), Xiphinema (380), Helicotylenchus (260), Ditylenchus (180), Rotylenchus (110), Tylenchorhynchus (90). The CCA results indicated the contribution of PPN species and soil variables in tomato farms to the analysis indicated that Meloidogyne and Rotylenchus were dominant in substrates characterized by soil structure (Clay, Silt%), and high-level of Ca (%), Carbon (%), and K (%) found in Polokwane and Tzaneen tomato farms. At the same time, Helicotylenchus, Pratylenchus, and Xiphinema were dominant in substrates characterized by sand (%), Na (%), and Mg (%) found in Giyani and Louis Trichardt tomato farms. In conclusion, soil factors can directly affect soil biology. In this study, the results showed unsustainable soil factor was the reason for the high plant-parasitic nematode population in the tomato field.