Pathogenicity and host‐parasite relationships of the root‐knot nematode Meloidogyne incognita on celery

Abstract

Pathogenicity and host-parasite relationships in root-knot disease of celery ( Apium graveolens ) caused by Meloidogyne incognita race 1 were studied under glasshouse conditions. Naturally and artificially infected celery cv. D'elne plants showed severe yellowing and stunting, with heavily deformed and damaged root systems. Nematode-induced mature galls were spherical and/or ellipsoidal and commonly contained more than one female, males and egg masses with eggs. Feeding sites were characterized by the development of giant cells that contained granular cytoplasm and many hypertrophied nuclei. The cytoplasm of giant cells was aggregated along their thickened cell walls and consequently the vascular tissues within galls appeared disrupted and disorganized. The relationship between initial nematode population density ( Pi ) and growth of celery plants was tested in glasshouse experiments with inoculum levels that varied from 0 to 512 eggs and second-stage juveniles (J 2 ) mL -1 soil. Seinhorst's model y = m + (1 -m ) z P-T was fitted to height and top fresh weight data of the inoculated and control plants. The tolerance limit with respect to plant height and fresh top weight of celery to M. incognita race 1 was estimated as 0·15 eggs and J 2 mL -1 soil. The minimum relative values ( m ) for plant height and top fresh weight were 0·37 and 0·35, respectively, at Pi ≥ 16 eggs and J 2 mL -1 soil. The maximum nematode reproduction rate ( Pf/Pi ) was 407·6 at an initial population density ( Pi ) of 4 eggs and J 2 mL -1 soil.

Studies on the Histopathological Responses of Vigna Mungo towards Meloidogyne Incognita at Different Time Intervals

“…Hyperplasia of the tissues adjacent to the giant cells contributed in the formation of root galls [18]. The orientation of xylem and phloem elements was changed because of hypertrophic and hyperplstic reactions taking place in infected region.…”

Plant paleopathology and the roles of pathogens and insects

“…While nematodes themselves produce disease symptoms in their hosts, they may also vector viral or bacterial diseases that produce, especially in roots, features such as galls (Vovlas et al, 2008), lesions and excessive branching. In above-ground shoots, nematodes are responsible for the yellowing and wilting of foliage (Brown et al, 1995), as well as swelling and shortened internode segments in stems and distortion of buds and leaf tissue.…”

Keragaman Komunitas Fitonematoda pada Sayuran Lahan Monokultur dan Polikultur di Sumatera Barat

“…Penggunaan pupuk organik dapat mempengaruhi populasi dan keberadaan nematoda. Menurut Vovlas et al (2008) nematoda menyebabkan kerugian yang nyata pada tanaman seledri. Strategi pengendalian yang digunakan ialah dengan nematisida, solarisasi tanah, bahan organik, pengendalian biologi, tanaman yang tahan nematoda.…”

“…≤25, aksidental; >25-50, assesori; >50-70, konstan; >75, absolut. menerus masih merupakan kisaran inang nematoda. Penggunaan lahan dengan musim tanam yang lama mengakibatkan beragamnya jenis patogen, salah satunya adalah keragaman nematoda (Vovlas et al 2008).…”