Role of Mycorrhizae and Some Biocontrol Agents to Control Root-Knot Nematodes on Tomato

Abstract

Tomato (Lycopersicon esulentum) are considered one of the most vegetable crops for export as well as its importances in food processing. These are grown in Egypt at different seasons throughout the year in opened field and greenhouse especially in newly reclaimed desert land. They are subjected to be attacked, and suffered from several fungal, bacterial, viral and nematode diseases. Plant parasitic nematodes are one of the most important pests worldwide especially root-knot nematodes (Meloidogyne spp.) on tomato which considered one of the most economically important that cause great harmful effect on plants and losses in quality and quantity of yield . Results obtained from this present investigation can be summarized as follows: Adding different biocontrol agents i.e. (Bacillus megaterium, Bacillus subtilis, Trichoderma harzianum, and Trichoderma spp.) resulted in soil cultivated with infectious tomato plants with root-knot nematode to reducing the numbers of nematodes and egg and egg sacs and larval phases. Arbuscular mycorrhizal fungi at different doses i.e. (0.5, 1 ,2 or 4%) and different application times (one week before, at the same time and one week after) nematode inoculation were evaluated on nematode parameters of tomato plants infected with Meloidogyne spp. Results showed that all different doses of arbuscular mycorrhizal fungisignificantly reduced all the nematode parameters i.e. number of galls, egg masses,. females / root system and number of J2 /250g soil compared to plants treated with nematode alone. Application AMF at 4% one week before nematode inoculation reduced the nematode parameters. The integration control of Meloidogyne spp. on tomato plants by using direct and indirect effect of the effective treatments were evaluated. Results of direct effect showed significantly reduction in all nematode parameters i. e. galls, egg masses and females / root system, as well as number of nematode juveniles. The greatest reduction in nematode parameters was recorded with the treatment of B. megaterium +T.harzianum + AMF 4% + Nematode and the integration control of Meloidogyne spp. on tomato plants by using indirect effect (split-root system) showed that the treatment of (B. megaterium + T. harzianum + AMF4% ) was the best treatment in controlling root-knot nematodes .

Extraction and Profiling of Antifungal Compounds Produced by Azotobacter Species

“…using sustainable, safe, and eco-friendly antagonistic bacteria is gaining importance in recent years. 27 Some of the microorganisms that possess antifungal activity against food pathogens are; Lactic acid bacteria, Propionibacterium, Bacillus, and Azotobacter. 28,29,12,13 Azotobacter is a prokaryote that fixes atmospheric nitrogen into ammonia, which can be easily assimilated in plants.…”