Plant parasitic nematodes associated with citrus trees and reaction of two citrus cultivars to Tylenchulus semipenetrans in northern Egypt

الملخص EN

A survey of plant-parasitic nematodes (PPN) associating citrus trees in Alexandria, El-Behera and Kafr El-Shiekh governorates, northern Egypt was carried-out during 2017 – 2019 growing seasons.

A total of 432 root and rhizosphere soil samples were collected from the surveyed citrus trees.

Nematodes were extracted using sieving and Bearmann-pan techniques and, identified to the generic level, based on the morphological characters.

Besides, the reaction of mandarine, Citrus deliciosa and lime, C.

aurantifolia against the citrus nematode, Tylenchulus semipenetrans, was determined under greenhouse conditions.

Results showed that 9 genera of PPN were found in association with the surveyed citrus trees in the three governorates.

The citrus nematode, Tylenchulus semipentrans was found to be very common (frequency of occurrence (FO) = 100% in all the surveyed locations, followed by the stubby root nematodes, Trichodorus spp., and the lesion nematodes, Pratylenchus spp.

The reaction of the two citrus cultivars; Mandarine, Citrus deliciosa and Lime, Citrus aurantifolia to T.

semipenetrans showed that the two cultivars are susceptible to all the tested populations of T.

semipentrans with a nematode reproduction factor (RF) was (1.67-2.6).The shoot and root dry weights of these cultivars were reduced as a result of the nematode infection.