Ten bacterial strains, selected from a bulk of isolates recovered from tomato rhizosphere, were tested for their ability to induce systemic resistance or bio-control agents against Meloidogyne incognita in tomato under greenhouse condition. Results showed that all ten tested bacterial strains showed significant reduction in nematode development and reproduction. The most effective strains were Methylomonas methanica, Bacillus cereus, Bacillus brevis and Obesumbacterium proteus. They were achieving the highest reduction in nematode total population and fecundity. Plant growth was improved as a result of application of rhizobacteria. Antioxidant enzymes activity for both peroxidase and polyphenol oxidase were elevated in bacteriazied plants compared nematode infected plant as well as total phenol content. Results revealed that crude culture suspension of bacteria was more effective for reducing nematode population followed by cell-free culture filtrates, bacterial live cells and bacterial dead cells suspension, sequentially. It was concluded that these bacteria able to suppress M. incognita as resistance inducers for tomato plants or bio-control agents.

The potency of the some chemicals from different groups known as inducers of systemic acquired resistance (SAR) viz., acetylsalicylic acid (ASA), DL-3aminobutyric acid (BABA), 2,6-dichloroisonicotinic acid (INA), 5-chlorosalicylic acid (CSA), nitrosalicylic acid (NSA),salicylic acid (SA),ascorbic acid (AS), and selenium (SE) in reducing reproduction Meloidogyne incognita in tomato plants cv. Castel rock was investigated under greenhouse conditions. Supplying chemicals three days-before nematode inoculation showed maximum efficacy in reducing nematode galls, egg-masses and eggs numbers followed by synchronized addition with inoculation, while post-inoculation treatment was less effective. Reiterative doses post-inoculation were improved the efficacy of single dose, also three doses used were more effective than one or two, while, differences between two or three doses were insignificant. On the other hand, plant fitness was slightly impaired with third dose than second one. INA and SE showed pronounced effect in inhibition nematode population after third dose compared with the rest chemicals, which showed mild increase in their efficacy from second to third doses. Unfortunately, three doses of SE were reduced plant fitness after enhanced by double doses, while INA was showed obvious phytotoxicity gradually increased by repeating doses. Gathering between the most effective application time (before inoculation) and the proper activated dose after inoculation was studies for emphasized their action and comparing with pre-inoculation only in suppressing M. incognita population. Chemical activators showed enhancing in peroxidase and polyphenoloxidase activities. In conclusion, CSA, NSA, BABA and SA were showed highest efficacy as resistance inducers. This collectively showed reduction of total population with pre-inoculation time application and pre plus post-inoculation application, 57.6&83.8%, 56.5&81.6%, 55.4&79.2% and 54.5&78.1%, respectively. Also the fecundity of nematode was taking similar trend as total population. The results suggest that tested chemicals especially CSA, NSA, BABA and SA have potential to suppress root-knot nematode infection in tomato plants through induced systemic resistance.

Resistance evaluation of 60 vegetable cultivars and hybrids of Eggplant, Pepper, Tomato, Cantaloupe, Cucumber and Squash were tested against Root-knot nematodes (RKN) Meloidogyne incognita. Among Eggplant genotypes, Arosy1 recorded the lowest reproduction rate (15.1) while the highest population was possessed by kaser abiad (41.1). Pepper genotypes, in general, were less susceptible to RKN compared with Eggplants and Tomatoes, the reproduction rate varied between 3.5 (Romey) to 8.9 (P77). All Tomato genotypes were highly susceptible to RKN infection, Super strain B was the most susceptible cultivar because the nematode success to multiply 38.3 times, the lowest reproduction rate (13.3) registered by 820 and Castel rock (11.6 & 11.8 respectively). Similarly, all cucurbitaceous plants found to be susceptible to RKN infection. Among Cantaloupe genotypes, Alhana possessed the highest reproduction rate (15.8), while Galia 3 recorded the lowest reproduction (7.2). Within Cucumber genotypes, the minimum reproduction rate (6.2) was observed on Almanar, but the maximum population was possessed by Aliaa (13.8). Squash genotypes viz. Sama recorded the lowest reproduction rate (4.8) and the greatest population (10.1) was possessed by Dahab. Plant growth in most cases negatively reacted with nematode infection and the differences between infected and healthy plant was unobvious in many cases. To recommend the less susceptible genotypes as a tool for managing nematode strategy, further experiments are needed in the field for using these selected genotypes, also insertion these genotypes in breeding program for improving their characters specially resistance to nematode.

Three amino acids (AAs) viz. glycine, L-proline and L-tryptophan plus yeast fungus, Saccharomyces cerevisiae, were tested against root knot disease, RKD, caused by root-knot nematode, Meloidogyne incognita on tomato cv. Super Strain-B. All AAs and yeast showed significant reduction in the number of galls, developmental stages, egg masses and fecundity of the treated plants associated with corresponding positive response in plant growth characters. Tryptophan gave significantly higher response in reducing the final nematode population followed by L-proline and glycine at high concentrations compared with yeast and check plants. In most cases, the soil drench application was more effective than foliar spray in reducing nematode build-up. The inhibitory effect of all treatments on nematode reproduction was positively correlated with increasing the concentration used. Plant growth was also promoted by all treatments used. Generally, All AAs gave significant impact in suppressing the development of the nematode pathogen and sequentially reliving the disease severity. Results of this research offered environmentally safe approaches for combating rootknot disease. Further researches are needed to determine the proper doses, and concentrations of tested AAs and yeast under semi-field and field conditions. Investigations must include the impact on plant yield, before recommending them for managing root-knot disease or promoting plant growth on a wide scale.

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