No abstract

Background Root-knot nematodes are among the world’s most damaging endoparasitic sedentary nematodes, especially, Meloidogyne incognita that infects a wide range of plant hosts. The activity of different antagonistic bacteria was studied for the low-cost and eco-friendly management of M. incognita on eggplant. Main body Twenty-five isolates were isolated from rhizosphere soils infected with nematodes. Of these, 6 isolates displayed the highest activity, demonstrating 100% mortality of J2 nematodes under laboratory conditions. Partial sequencing of 16S rRNA gene and phylogenetic analysis was used to identify the selected isolates and they were found to be Paenibacillus amylolyticus, Brevibacillus agri, Gluconobacter frateurii, Beijerinckia mobilis, Achromobacter aloeverae, and Pseudomonas stutzeri. The abilities of the selected isolates to produce hydrogen cyanide, siderophores, chitinase, protease, indole acetic acid, and to dissolve phosphorus were also detected. Conclusion The results of the greenhouse experiment indicated that all the tested bacteria had a greatly significant effectiveness for suppressing root-knot nematode M. incognita. Application of all the rhizosphere bacteria and their combinations reduced the number of galls, number of juveniles, egg-masses, eggs, females, and total final population. All bio-agent treatments succeeded in improving the plant growth parameters and increased the microbial density in eggplant rhizosphere.

Two types of compost, (plant and animal) as well as furan 10%G were effective in reducing Meloidogyne incognita number of galls, nematode reproduction and fecundity. Compost was investigated as amendment for suppressing populations of Meloidogyne incognita and increasing plant vigor. The greenhouse and laboratory studies were conducted with mature compost produced in SEKEM organic farm. Compost extract was prepared by steeping 100 g compost in 200 ml tap water and removing biomass with cheesecloth filtration followed by centrifugation. The supernatant was diluted I: 4 in water, sterile filtered and used as I00% compost extract treatment. In micro well as says, M. incognita J 2 activity were inhibited by all tested compost extract concentrations (25%, 50%, 75% and 100% extract), with >55% inhibition in 100% compost extract after 72h. (Animal and plant) Compost treatments mixed with soil at doses 25, 50,100g/ kg were greater treatment gave the best result in reducing the nematode reproduction compared with untreated check. (Animal and plant) compost suppressing final nematode population values that average 92.18% and 92.54 respectively, at doses 100g/kg soil compared with nematicide Furan 10% at dose 2g/ kg suppressing final nematode population values that average 79.10%. Also the used (animal and plant) compost tea at two times 2 days before inoculation and 10 days after inoculation showed the same results. The highest percentage of reduction in nematode final population (80.59%) and (82.90%) was noticed in concentration dose100 g/200 cm 3 water / kg by animal and plant compost tea 2 days before inoculation.All the tested materials significantly suppressed nematode final population and rate of buildup. In general there were positive correlation between the concentration used and the obtained degree of nematode management.