Mahdy, Magdy: Biological control of plant parasitic nematodes with antagonistic bacteria on different host plants. - Bonn, 2002. - Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn.
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5n-02036
@phdthesis{handle:20.500.11811/1765,
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5n-02036,
author = {{Magdy Mahdy}},
title = {Biological control of plant parasitic nematodes with antagonistic bacteria on different host plants},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2002,
note = {Root-knot nematodes, Meloidogyne spp., are recognized as the most economically important genus of plant parasitic nematodes worldwide. The nematode causes severe damage and yield loss to a large number of cultivated plants and especially on vegetable crops in the tropics and subtropics. In the investigations conducted in this study, the potential control of plant parasitic nematodes using different antagonistic bacteria was studied with particular reference to the control of species of Meloidogyne on tomato.
The results obtained from the research are presented in four chapters. The first chapter gives a: comprehensive
introduction to the problems associated with root-knot nematode attack, outlines the major control methods being used and and gives an insite into integrated pest management now as well as the potential use of biological control in future integrated strategies for nematode management.
In the second chapter the results of experiments on the biological control activity of the plant health promoting rhizobacterium Bacillus cereus strain S18 for biocontrol of the three major species of Meloidogyne are discussed. The results showed that B. cereus introduced either as a soil drench or as a root dip, reduced the number of galls and egg masses of M. incognita on tomato significantly. B. cereus applied 10 days before nematode inoculation caused significant reductions in root galling and number of galls. No differences, however, were detected between the different application times in the number of egg masses produced. It was also shown that B. cereus does not control all three major species of Meloidogyne to the same degree. B. cereus had little to no biological control activity toward M. arenaria, but gave significant control of M. incognita and M. javanica. Furthermore, the results demonstrated that B. cereus is an effective biological control agent of M. incognita on a broad spectrum of host plants. 
In the third chapter the plant health promoting rhizobacterium Rhizobium etli strain G12 was tested for control of different genera of plant parasitic nematodes on a broad spectrum of crops. R. etli exhibited strong biocontrol activity towards M. incognita on different host plants. The reduction rates varied however between crops. Results showed that R. etli had the ability to control three economically important species of Meloidogyne. The highest reduction was against M. incognita and M. javanica, whereas it had little effect on M. arenaria. It was also demonstrated that increasing inoculum densities of R. etli caused increased reductions in nematode infection. Reduction in the number of galls occurred at 1010 cfu/ml whereas reductions in egg mass number were detected at 106 to 1010 cfu/ml. R. etli also caused significant reductions in sugar beet cyst nematode, Heterodera schachtii infection. R. etli reduced significantly the number of cysts/plant and number of eggs and juveniles/plant. The bacteria, however, did not affect the number of eggs and juveniles/cyst. The experimental data also showed that R. etli can reduce infection of the cyst nematode Globodera pallida on potato, but had no activity towards the migratory endoparasitic root-lesion nematode Pratylenchus zeae on maize.  
In the fourth chapter the spore-forming endoparasitic bacterium Pasteuria penetrans (Pp3) was used as a biocontrol agent for the biological control of M. javanica on tomato. The results revealed abiotic factors affect attachment. Culture filtrates of the two antagonistic rhizobacteria B. cereus S18 and R. etli G12 reduced attachment of Pp3 spores to the cuticle of M. javanica juveniles at 100 strength and dilutions of 10 percent of the original fermentation broth. The experiments also demonstrated that percolates of chicken manure compost treated soil had a strong negative effect on the attachment of Pp3 spores to M. javanica juveniles. In greenhouse tests P. penetrans multiplied quickly and within 6 months and gave good biological control of M. javanica when initially introduce into the planting soil during seedling production. The seedlings with P. penetrans in the potting soil were then grown for two additional tomato cropping cycles in a sand substrate previously infested with root-knot nematodes, at temperatures above 25 C. The overall results of these studies demonstrated the importance of three different bacterial antagonists for root-knot nematode control and supplied new information on how to improve activity of the bioloigcal control agents as well as ideas on their use in integrated management under field conditionsstudies demonstrated the importance of three different bacterial antagonists for root-knot nematode control and supplied new information on how to improve activity of the bioloigcal control agents as well as ideas on their use in integrated management under field conditions. },

url = {http://hdl.handle.net/20.500.11811/1765}
}

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