Prevalence of Root-Knot Nematodes, Meloidogyne spp. in Greenhouse Tomato Crops in the Syrian Coastal Region

Abstract

Root-knot nematodes (RKN), Meloidogyne spp. are among the most widespread and damaging plant-parasitic nematodes to various crops worldwide. This research aimed to survey the distribution of these nematodes on tomato plants in greenhouses along the Syrian coast, estimate the severity of their infection, and compare their spread and infection severity between sites, varieties/hybrids and different soil treatment methods (solar sterilization or chemical nematicides). From 67 locations at Latakia and Tartous governorates, 273 Samples were collected from soils and tomato roots during 2023 and 2024 seasons. Motile individuals of root-knot nematodes (second-stage juveniles and males) were extracted, and their numbers in each sample were estimated. The severity on root infection was also estimated based on the number of galls formed. The results showed that RKN were found on tomato plants in greenhouses in the studied sites, with a higher incidence in Tartous Governorate. The results also revealed a correlation between each of the density and severity of infection of different plant varieties (the highest population was found on the Ninar variety with 13,201 individuals/250 cm³ of soil), and with the treatment methods used (the highest density was found in untreated greenhouses with 20,872 individuals/250 cm³ of soil). Density was also correlated to the plant’s phenological stage, with an increase observed with plant age, reaching the highest count during the fruiting stage (4,017 individuals/250 cm³ of soil). Infestation severity generally varied between 3.7 and 8.5. This study served as an update on the occurrence of RKN on tomato greenhouses in the Syrian coast and should be followed by a study of their spread on other crops in greenhouses.

Keywords:

Infection severity, Meloidogyne, natural distribution, root-knot nematode, Syrian coast, tomato.