In two laboratory experiments and one pot experiment the in uence of the bacterial symbionts Pseu... more In two laboratory experiments and one pot experiment the in uence of the bacterial symbionts Pseudomonas oryzihabitans from Steinernema abbasi and Xenorhabdus nematophilus from S. carpocapsae on the root-knot nematode Meloidogyne javanica was investigated. Exposure of egg masses of M. javanica to the bacteria and their metabolites resulted in reduced hatching of second stage juveniles (J2). J2 in contact with the bacteria and their metabolites exhibited disorientation and convulsive movements, but when they were washed and placed in fresh water, many regained normal movement. At dosages of 10 6 and 10 7 cells ml 1 mortality was 100% after 24 h exposure, Xenorhabdus being more toxic than Pseudomonas. In soil X. nematophilus was ineffective but P. oryzihabitans prevented invasion of J2 into tomato roots and there was evidence that the bacterium or its metabolites interfered with nematode development in galls. Overall, the results indicate that P. oryzihabitansmay provide a possible control strategy for root-knot nematodes. Résumé-Action nématicide des bactéries Pseudomonas oryzihabitans et Xenorhabdus nematophilus sur le nématode Meloidogyne javanica-Les présentes recherches, au travers de deux expériences au laboratoire et d'une troisième en pots, ont concerné l'in uence sur le nématode Meloidogyne javanica des symbiontes bactériens Pseudomonas oryzihinabitans, provenant de Steinernema abbasi, et Xenorhabdus nematophilus, de S. carpocapsae. L'exposition de masses d'oeufs de M. javanica aux bactéries et à leurs métabolites a provoqué une diminution de l'éclosion des juvéniles de deuxième stade (J2). Les J2 en contact avec les bactéries et leurs métabolites se sont montrés désorientés et sujets à des mouvements convulsifs mais, après qu'ils aient été lavés et placés dans une eau pure, bon nombre d'entre eux ont recouvré des mouvements normaux. Aux doses de 10 6 et 10 7 cellules/ml 1 la mortalité était de 100% après une exposition de 24 h, Xenorhabdus s'étant révélé plus toxique que Pseudomonas. Dans le sol, Xenorhabdus s'est montré inef cace tandis que Pseudomonas empêchait la pénétration des J2 dans les racines de tomate; de plus, il semblerait évident que les bactéries ou leurs métabolites aient une in uence sur le développement des nématodes dans les galles. Dans l'ensemble, les résultats indiquent que P. oryzihinabitans peut fournir une éventuelle stratégie de contrôle envers les Meloidogyne.
Efficacy of the bacterial cell suspensions from entomopathogenic nematode Steinernema abbasi against larvae and pupae of Spodoptera exigua and Galleria mellonella
The susceptibility of the second stage juveniles of Meloidogyne javanica to the bacterial symbiont from the entomopathogenic nematode, Steinernema abbasi (Steinernematidae: Nematoda)
Progeny production of Steinernema abbasi in lepidopterous larvae
International Journal of Pest Management, 2001
... (Keywords: progeny production, entomopathogenic nematodes, Steinernema abbasi) SAMI A. ELAWAD... more ... (Keywords: progeny production, entomopathogenic nematodes, Steinernema abbasi) SAMI A. ELAWAD*, SR GOWEN and NGM HAGUE ... References ADKINSON, PL, VANDERZANT, ES, BUFF, DL and ALLISON, WE, 1960. A wheat germ medium for rearing the pink boll worm. ...
The entomopathogenic bacterium, Xenorhabdus nematophila was isolated from the hemolymph of Galler... more The entomopathogenic bacterium, Xenorhabdus nematophila was isolated from the hemolymph of Galleria mellonella infected with Steinernema carpocapsae. The bacterial cells and its metabolic secretions have been found lethal to the Galleria larvae. Toxic secretion in broth caused 95% mortality within 4 d of application whereas the bacterial cells caused 93% mortality after 6 d. When filter and sand substrates were compared, the later one was observed as appropriate. Similarly, bacterial cells and secretion in broth were more effective at 14% moisture and 25 °C temperature treatments. Maximum insect mortality (100%) was observed when bacterial concentration of 4×10 6 cells/ml was used. Similarly, maximum bacterial cells in broth (95%) were penetrated into the insect body within 2 h of their application. However, when stored bacterial toxic secretion was applied to the insects its efficacy declined. On the other hand, when the same toxic secretion was dried and then dissolved either in broth or water was proved to be effective. The present study showed that the bacterium, X. nematophila or its toxic secretion can be used as an important component of integrated pest management against Galleria.
Japanese journal of applied entomology and zoology, 1998
The pathogenicities of five isolates of Beauveria bassiana to Plutella xylostella were investigat... more The pathogenicities of five isolates of Beauveria bassiana to Plutella xylostella were investigated. Treatment of 4th-instar larvae with each isolate resulted in 0%-100% mortalities at 5 days after inoculation. Detailed studies were made on the most virulent isolate, MG-Bb-1, obtained from P. xylostella, to determine its efficacy at different developmental stages of P. xylostella, doses, and humidities. MG-Bb-1 had high pathogenicity to lervae of all instars, but little pathogenicity to eggs, and almost no pathogenicity to pupae. Humidity influenced the virulence to 4th-instar larvae; MG-Bb-1 caused mortality of over 80% at 76% RH or higher levels, but only 30% mortality at 52% RH. A conidial suspension (107/ml) of MG-Bb-1 was sprayed on a cabbage field to control P. xylostella. A single application controlled P. xylostella as well as Flufenoxuron.
In two laboratory experiments and one pot experiment the influence of the bacterial symbionts Pse... more In two laboratory experiments and one pot experiment the influence of the bacterial symbionts Pseudomonas oryzihabitans from Steinernema abbasi and Xenorhabdus nematophilus from S. carpocapsae on the root-knot nematode Meloidogyne javanica was investigated. Exposure of egg masses of M. javanica to the bacteria and their metabolites resulted in reduced hatching of second stage juveniles (J2). J2 in contact with the bacteria and their metabolites exhibited disorientation and convulsive movements, but when they were washed and placed in fresh water, many regained normal movement. At dosages of 106 and 107 cells ml-1 mortality was 100% after 24 h exposure, Xenorhabdus being more toxic than Pseudomonas. In soil X. nematophilus was ineffective but P.oryzihabitans prevented invasion of J2 into tomato roots and there was evidence that the bacterium or its metabolites interfered with nematode development in galls. Overall, the results indicate that P.oryzihabitans may provide a possible cont...
Steinernema riobrave was originally isolated from prepupae and pupae of the bollworms Helicoverpa... more Steinernema riobrave was originally isolated from prepupae and pupae of the bollworms Helicoverpa zea (Boddie) and Spodoptera frugiperda (J.E. Smith) in the Lower Rio Grande Valley by Raulston et al. (1992) and described by Cabanillas and Raulston (1994). Steinernema abbasi, recovered from soil in an alfalfa eld in the Sultanate of Oman by Mr M. Hubeis, was described by Elawad et al. (1997). The natural host of S. abbasi was not found but the common insect pests in the alfalfa eld were Helicoverpa armigera (Hübner) and Spodoptera littoralis (Boisduval). Both nematode species are from the semiarid tropics and their optimum temperature for infection and establishment in the susceptible host Galleria mellonella is between 25 and 30°C (Elawad et al., 1996). The infection and establishment of entomopathogenic nematodes is very temperature dependant (Grewal et al., 1994). Development of steinernematids has been shown to be fastest at their optimum temperature for establishment; S. carpocapsae (UK isolate) at 25°C in larch saw y, Cephalcia lariciphila Georgis (1981), and S. arenarium (= S. anamoli) at 22°C in Galleria mellonella (Poinar & Kozodoi, 1988). In this paper, the life cycle of S. abbasi and S. riobrave is described at the optimum temperature range for establishment of 25-30°C. The time after infection at which the dauer juveniles (DJ) emerge from infected larvae of Galleria mellonella was investigated. Materials and methods NEMATODE CULTURE Steinernema abbasi was isolated from soil in an alfalfa eld using the Galleria baiting technique (Bedding & Akhurst, 1975). The isolate of S. riobrave was supplied by Biosys Inc., Palo Alto, CA. The nematodes were cultured in the greater wax moth Galleria mellonella at 25°C and dauer juveniles harvested using White Traps (White,
Résumé - Steinernema abbasi sp. n. (Nem.atoda : Steinernem.atidae) originaire du Sulatanat d'... more Résumé - Steinernema abbasi sp. n. (Nem.atoda : Steinernem.atidae) originaire du Sulatanat d'Oman - Description est donnée de Sceinernema abbasi sp. n., extrait du sol de champs de luzerne dans le Sultanat d'Oman. S. abbasi sp, n, provient d'environnements ...
In two laboratory experiments and one pot experiment the in uence of the bacterial symbionts Pseu... more In two laboratory experiments and one pot experiment the in uence of the bacterial symbionts Pseudomonas oryzihabitans from Steinernema abbasi and Xenorhabdus nematophilus from S. carpocapsae on the root-knot nematode Meloidogyne javanica was investigated. Exposure of egg masses of M. javanica to the bacteria and their metabolites resulted in reduced hatching of second stage juveniles (J2). J2 in contact with the bacteria and their metabolites exhibited disorientation and convulsive movements, but when they were washed and placed in fresh water, many regained normal movement. At dosages of 10 6 and 10 7 cells ml 1 mortality was 100% after 24 h exposure, Xenorhabdus being more toxic than Pseudomonas. In soil X. nematophilus was ineffective but P. oryzihabitans prevented invasion of J2 into tomato roots and there was evidence that the bacterium or its metabolites interfered with nematode development in galls. Overall, the results indicate that P. oryzihabitansmay provide a possible control strategy for root-knot nematodes. Résumé-Action nématicide des bactéries Pseudomonas oryzihabitans et Xenorhabdus nematophilus sur le nématode Meloidogyne javanica-Les présentes recherches, au travers de deux expériences au laboratoire et d'une troisième en pots, ont concerné l'in uence sur le nématode Meloidogyne javanica des symbiontes bactériens Pseudomonas oryzihinabitans, provenant de Steinernema abbasi, et Xenorhabdus nematophilus, de S. carpocapsae. L'exposition de masses d'oeufs de M. javanica aux bactéries et à leurs métabolites a provoqué une diminution de l'éclosion des juvéniles de deuxième stade (J2). Les J2 en contact avec les bactéries et leurs métabolites se sont montrés désorientés et sujets à des mouvements convulsifs mais, après qu'ils aient été lavés et placés dans une eau pure, bon nombre d'entre eux ont recouvré des mouvements normaux. Aux doses de 10 6 et 10 7 cellules/ml 1 la mortalité était de 100% après une exposition de 24 h, Xenorhabdus s'étant révélé plus toxique que Pseudomonas. Dans le sol, Xenorhabdus s'est montré inef cace tandis que Pseudomonas empêchait la pénétration des J2 dans les racines de tomate; de plus, il semblerait évident que les bactéries ou leurs métabolites aient une in uence sur le développement des nématodes dans les galles. Dans l'ensemble, les résultats indiquent que P. oryzihinabitans peut fournir une éventuelle stratégie de contrôle envers les Meloidogyne.
Efficacy of the bacterial cell suspensions from entomopathogenic nematode Steinernema abbasi against larvae and pupae of Spodoptera exigua and Galleria mellonella
The susceptibility of the second stage juveniles of Meloidogyne javanica to the bacterial symbiont from the entomopathogenic nematode, Steinernema abbasi (Steinernematidae: Nematoda)
Progeny production of Steinernema abbasi in lepidopterous larvae
International Journal of Pest Management, 2001
... (Keywords: progeny production, entomopathogenic nematodes, Steinernema abbasi) SAMI A. ELAWAD... more ... (Keywords: progeny production, entomopathogenic nematodes, Steinernema abbasi) SAMI A. ELAWAD*, SR GOWEN and NGM HAGUE ... References ADKINSON, PL, VANDERZANT, ES, BUFF, DL and ALLISON, WE, 1960. A wheat germ medium for rearing the pink boll worm. ...
The entomopathogenic bacterium, Xenorhabdus nematophila was isolated from the hemolymph of Galler... more The entomopathogenic bacterium, Xenorhabdus nematophila was isolated from the hemolymph of Galleria mellonella infected with Steinernema carpocapsae. The bacterial cells and its metabolic secretions have been found lethal to the Galleria larvae. Toxic secretion in broth caused 95% mortality within 4 d of application whereas the bacterial cells caused 93% mortality after 6 d. When filter and sand substrates were compared, the later one was observed as appropriate. Similarly, bacterial cells and secretion in broth were more effective at 14% moisture and 25 °C temperature treatments. Maximum insect mortality (100%) was observed when bacterial concentration of 4×10 6 cells/ml was used. Similarly, maximum bacterial cells in broth (95%) were penetrated into the insect body within 2 h of their application. However, when stored bacterial toxic secretion was applied to the insects its efficacy declined. On the other hand, when the same toxic secretion was dried and then dissolved either in broth or water was proved to be effective. The present study showed that the bacterium, X. nematophila or its toxic secretion can be used as an important component of integrated pest management against Galleria.
Japanese journal of applied entomology and zoology, 1998
The pathogenicities of five isolates of Beauveria bassiana to Plutella xylostella were investigat... more The pathogenicities of five isolates of Beauveria bassiana to Plutella xylostella were investigated. Treatment of 4th-instar larvae with each isolate resulted in 0%-100% mortalities at 5 days after inoculation. Detailed studies were made on the most virulent isolate, MG-Bb-1, obtained from P. xylostella, to determine its efficacy at different developmental stages of P. xylostella, doses, and humidities. MG-Bb-1 had high pathogenicity to lervae of all instars, but little pathogenicity to eggs, and almost no pathogenicity to pupae. Humidity influenced the virulence to 4th-instar larvae; MG-Bb-1 caused mortality of over 80% at 76% RH or higher levels, but only 30% mortality at 52% RH. A conidial suspension (107/ml) of MG-Bb-1 was sprayed on a cabbage field to control P. xylostella. A single application controlled P. xylostella as well as Flufenoxuron.
In two laboratory experiments and one pot experiment the influence of the bacterial symbionts Pse... more In two laboratory experiments and one pot experiment the influence of the bacterial symbionts Pseudomonas oryzihabitans from Steinernema abbasi and Xenorhabdus nematophilus from S. carpocapsae on the root-knot nematode Meloidogyne javanica was investigated. Exposure of egg masses of M. javanica to the bacteria and their metabolites resulted in reduced hatching of second stage juveniles (J2). J2 in contact with the bacteria and their metabolites exhibited disorientation and convulsive movements, but when they were washed and placed in fresh water, many regained normal movement. At dosages of 106 and 107 cells ml-1 mortality was 100% after 24 h exposure, Xenorhabdus being more toxic than Pseudomonas. In soil X. nematophilus was ineffective but P.oryzihabitans prevented invasion of J2 into tomato roots and there was evidence that the bacterium or its metabolites interfered with nematode development in galls. Overall, the results indicate that P.oryzihabitans may provide a possible cont...
Steinernema riobrave was originally isolated from prepupae and pupae of the bollworms Helicoverpa... more Steinernema riobrave was originally isolated from prepupae and pupae of the bollworms Helicoverpa zea (Boddie) and Spodoptera frugiperda (J.E. Smith) in the Lower Rio Grande Valley by Raulston et al. (1992) and described by Cabanillas and Raulston (1994). Steinernema abbasi, recovered from soil in an alfalfa eld in the Sultanate of Oman by Mr M. Hubeis, was described by Elawad et al. (1997). The natural host of S. abbasi was not found but the common insect pests in the alfalfa eld were Helicoverpa armigera (Hübner) and Spodoptera littoralis (Boisduval). Both nematode species are from the semiarid tropics and their optimum temperature for infection and establishment in the susceptible host Galleria mellonella is between 25 and 30°C (Elawad et al., 1996). The infection and establishment of entomopathogenic nematodes is very temperature dependant (Grewal et al., 1994). Development of steinernematids has been shown to be fastest at their optimum temperature for establishment; S. carpocapsae (UK isolate) at 25°C in larch saw y, Cephalcia lariciphila Georgis (1981), and S. arenarium (= S. anamoli) at 22°C in Galleria mellonella (Poinar & Kozodoi, 1988). In this paper, the life cycle of S. abbasi and S. riobrave is described at the optimum temperature range for establishment of 25-30°C. The time after infection at which the dauer juveniles (DJ) emerge from infected larvae of Galleria mellonella was investigated. Materials and methods NEMATODE CULTURE Steinernema abbasi was isolated from soil in an alfalfa eld using the Galleria baiting technique (Bedding & Akhurst, 1975). The isolate of S. riobrave was supplied by Biosys Inc., Palo Alto, CA. The nematodes were cultured in the greater wax moth Galleria mellonella at 25°C and dauer juveniles harvested using White Traps (White,
Résumé - Steinernema abbasi sp. n. (Nem.atoda : Steinernem.atidae) originaire du Sulatanat d'... more Résumé - Steinernema abbasi sp. n. (Nem.atoda : Steinernem.atidae) originaire du Sulatanat d'Oman - Description est donnée de Sceinernema abbasi sp. n., extrait du sol de champs de luzerne dans le Sultanat d'Oman. S. abbasi sp, n, provient d'environnements ...
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