الفهرس 
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Abstract
Bacterial spot disease of tomato is one of the most important bacterial diseases infects tomato plants either under greenhouse or field conditions, worldwide and in Egypt. The disease can affect leaves, petioles, stems and fruits, and causes a big loss. Bacterial spot becomes more aggressive in high temperature and high humidity conditions. It is well known that tomato crop is one of the most important economically crops, which is cultivated using many different cultivars. Some of these cultivars may be susceptible while others may be resistant against bacterial spot. So the aim of this work was to know the susceptibility or resistance of some tomato cultivars to infection with bacterial spot, also to find out some biochemical changes within infected plants duo to infection, in comparison to healthy plants. We also aimed at studying the diversity between different isolates of the pathogen occurred in Egypt. Finally trying to evaluate different foliar treatments (biotic or abiotic) for controlling the disease.
The results obtained can be summarized as follows:
1- Ninety infected tomato samples were collected from different locations from Beheira (27), Qalyubiya (38) and Sharkia (25) governorates during 2007 and 2008 in Egypt. After isolation and purification of the causal organism on the semi-selective medium, 64 samples gave positive results.
2- Pathogenicity test was carried out for obtained isolates (64 isolates) on tomato seedlings, where 47 isolates only were pathogenic according to typical symptoms as small spots appear as water-soaked, light to dark green areas on infected leaves at the beginning, then, they turn into greasy brown spots, sometimes they surrounded by a yellow hallo.
3- Based on morphological, cultural, physiological and biochemical characters, all isolates were identified as Xanthomonas campestris pv. Vesicatoria.
4- Two isolates (TX5 and TX1) were selected, and identified using Biolog system to confirm the identification as X. vesicatoria, 96% and 86% respectively.
5- Ten isolates of X. vesicatoria were selected to compare their cultural characters, pathogenicity test and molecular differences.
6- In case of cultural characters, Tween B medium and nutrient agar medium were used to differentiate between isolates.
7- High cultural variation was noticed between isolates on Tween B and Nutrient agar media, where some isolates possessed large colonies while others had smaller ones, also some isolates were pale-yellow in color and other isolates were dark-yellow.
8- In case of pathogenicity, examined isolates showed differences in their virulence, where isolates TX5 and Tx1 were high pathogenic, while isolates TX3, TX4, PX4 and PX2 were moderately pathogenic, however isolates TX2, PX5, PX3 and PX1 were low pathogenic.
9- One RAPD primer was used with ten X. vesicatoria isolates genome to detect DNA marker(s) for virulence or avirulence linked with bacterial spot disease in tomato.
10- All ten isolates of X. vesicatoria were different in their genome, and the two highly pathogenic isolates (TX1 and TX5) showed a distinct band that is not present in the genome of other isolates, which can be used as a marker of virulence.
11- Seven tomato cultivars were evaluated against bacterial spot disease, using a virulent isolate. Castle Rock, cv. Was the most susceptible cultivar against the disease, while cultivar H 339 was the least susceptible cultivar.
12- Activity of 3 defence related enzymes (peroxidase, polyphenol oxidase and phenylalanine ammonia lyase) were assessed in 5 tomato cultivars (infected and healthy). Enzyme levels were increased in diseased plants in comparison to healthy plants. There was no correlation between enzyme levels and disease severity.
13- For disease control, different bactericides, commercial bioagent products and resistance inducers were evaluated.
14- Effect of bactericides (streptomycin sulphate, Kocide 101 and Galbin copper) at different concentrations on X.v growth in vitro was carried tested.
15- Streptomycin sulphate was the most effective bactericide that inhibited X.v growth in vitro.
16- Effect of 4 bioagents (Symbion N-G, Symbion N-R, Bio-Cure-B, Bio-Cure-F) at different concentrations on X.v growth in vitro was evaluated.
17- Bio-Cure-B showed the highest effect in inhibiting growth of X.v growth in vitro followed by Bio-Cure-F.
18- Effect of resistance inducers (acetylsalicylic acid, salicylic acid and Bion) at different concentrations on X.v growth in vitro was tested.
19- All resistance inducers at tested concentration did not inhibit growth of X.v, in vitro.
20- All tested bactericides at different concentrations were used under artificial inoculation conditions in a greenhouse as a foliar treatment before or after pathogen infection.
21- Streptomycin sulphate was the most effective bactericide against the pathogen and significantly reduced disease severity.
22- Streptomycin sulphate also, was the most effective bactericide on bacterial spot disease severity.
23- Efficiency of bactericides was increased with increasing the used concentration.
24- All tested bioagents with different concentrations, were used under artificial inoculation conditions in a greenhouse as a pre inoculation treatment or a post inoculation treatment.
25- Bio-Cure-B was the most effective bioagent against the pathogen and significantly reduced disease severity followed by Bio-Cure-F when used as a pre or a post treatment.
26- Using Bio-Cure-B as a pre treatment was more effective than using it as a post treatment.
27- Efficiency of bioagents increases with increasing the used concentration.
28- Three resistance inducers with different concentrations, were used under artificial inoculation conditions in a greenhouse as a pre inoculation treatment or a post inoculation treatment.
29- Salicylic acid was the most effective inducer against the pathogen and significantly reduced disease severity followed by acetylsalicylic acid when used as a pre or a post treatment.
30- Using salicylic acid as a pre treatment was more effective than using it as a post treatment, however, efficiency of inducers increases with increasing the used concentration.