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Feeding sites of Heterodera latipons in wheat, barley and Lolium rigidum were studied and compared with those of Heterodera avenae in wheat. Juveniles of H. latipons penetrated mainly differentiated roots and chose a root cortical cell as their initial syncytium cell (ISC) in wheat and barley, whilst H. avenae chose a vascular parenchymal cell as an ISC. The cell associated with females in wheat root underwent hypertrophy, and incorporated endodermis, pericycle and parenchyma cells of the vascular cylinder by cell wall dissolution. Syncytia of H. latipons contained a high number of organelles, including endoplasmic reticulum, mitochondria, plastids and amoeboid nuclei, whilst those of H. avenae were highly vacuolated. The syncytium partly occupied both the cortex and the vascular cylinder in contrast to those of H. avenae, which occupied most of the space within the vascular cylinder near the infection site. The cortical cell associated with H. latipons males did not undergo hypertrophy, but had dense cytoplasm, and incorporation of other cells by cell wall dissolution was rare. A similar syncytium formation process was observed with barley, but a cortical cell, several cell layers away from the endodermis, was chosen for the ISC. In resistant L. rigidum, H. latipons juveniles chose an endodermal cell or its neighbouring cortical cell as an ISC. Partial dissolution of cell wall was observed in neighbouring parenchymal cells, although the nematode did not develop into adults. [ABSTRACT FROM AUTHOR]

Heterodera sacchari, H. leuceilyma and H. goldeni are closely related members of the H. sacchari species complex, which is mainly characterised and distinguished from all other described Heterodera species by the presence of finger-like projections of the strongly developed underbridge in the vulval cone of the cysts. Males are rare in all three species and are described here in H. goldeni for the first time. Reproduction appears to be parthenogenetic. There are only minor morphological distinctions between the three species, particularly after our present studies have emended their original descriptions from various populations. Heterodera sacchari and H. goldeni showed differences in the ITS-rRNA gene sequences. Heterodera sacchari was described and reliably identified from many tropical African countries, H. leuceilyma is known only from Florida, USA, and H. goldeni has been identified in Egypt, Israel and Iran. All three species have grasses and other Poaceae as hosts, H. sacchari commonly attacking rice and sugarcane, and H. goldeni reproducing successfully on sugarcane ratoon seedlings. Morphological data emending the descriptions of H. sacchari, H. goldeni and H. leuceilyma from various populations are presented and discussed along with their host and distribution. Molecular characterisation of H. sacchari and H. goldeni is provided. An analysis of phylogenetic relationships within species of the sacchari-group using ITS-rRNA gene sequences is also presented. [ABSTRACT FROM AUTHOR]

A population of a root-knot nematode species was isolated from Zoysia japonica in a turf nursery in Israel. Measurements and morphology of the second-stage juveniles and adult females, including perineal pattern, indicated this nematode to be Meloidogyne marylandi. In addition, esterase (Est) and malate dehydrogenase (Mdh) isozymes were studied for the first time for this species which is shown to be characterised by VS1 Est band and a N1c Mdh pattern. Host range tests showed that the turf grasses Stenotaphrum secundatum, Dactyloctenium australe and Paspalum vaginatum, corn (Zea mays) and oat (Avena sativa) were non-hosts or resistant. Kikuyu grass (Pennisetum clandestinum), wheat (Triticum aestivum), barley (Hordeum vulgare), bristle oat (Avena strigosa), Siberian millet (Echinochloa frumentaceae) and pearl millet (Pennisetum glaucum) were susceptible to the nematode. The second-stage juveniles of M. marylandi penetrated the elongation zone of wheat roots but did not reach the meristematic zone and settled with their anterior end toward the root tip. This contrasted with M. javanica or M. incognita which migrated to the meristematic zone, and turned around with their anterior toward the root base. Meloidogyne marylandi juveniles induced giant cells from vascular parenchyma cells and caused no or only small galls on the roots. [ABSTRACT FROM AUTHOR]

New nematode control measures are required due to the likely removalof effective nematicides from the market because of increasing concerns of possible effects on human health and the environment. Biological control, organic and inorganic soil amendments, naturally occurring nematicides, induced resistance, interruption of host recognition and transgenic plants will be a part of integrated management of plant-parasitic nematodes in the near future. The paper reports work carried out in Israel on these topics. [ABSTRACT FROM AUTHOR]