Aim:The aims of the study were to isolate and characterize the nematode trapping fungus, Arthrobotrys oligospora, to investigate the suppressive and predacious activities of the fungus against Meloidogyne incognita and to study the potentiality of A. oligospora in controlling root-knot caused by M. incognita on tomato plants. Methods and Results: Arthrobotrys oligospora (MRDS 300) was isolated from sandy soil samples collected from Al-Beheira, Egypt. In vitro experiments revealed a high efficiency of the fungus in capturing and suppressing M. incognita second juveniles (J 2 ). Microscopic observations showed that the fungus develops adhesive traps consisting of loops of hyphae. Moreover, an in vitro experiment showed that the culture filtrate of A. oligospora had a high toxic effect on the nematode. Pot experiments carried out in two seasons (2018-2019) showed that A. oligospora significantly suppressed root knot on tomato plants caused by M. incognita. The number of females, galls and nematodes in different developing stages were reduced significantly. The treatment with A. oligospora had a prominent effect on enhancing plant growth. Conclusion: Arthrobotrys oligospora had significant suppressive and predacious effects against root-knot nematode, M. incognita. The fungus developed different forms of trapping devices in addition to secreting toxic metabolites to M. incognita. The fungus had a plant-growth promoting effect. Significance and Impact of the Study: Arthrobotrys oligospora (MRDS 300) is a potential biological control agent that can be utilized in controlling the rootknot diseases caused by M. incognita.

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Our investigation aimed to evaluate the efficacy of applying Boric, Ascorbic and Oxalic acids as foliar treatments on two strawberry cultivars, i.e., Fortuna and Sensation, during field growth, on controlling gray mold in postharvest stage. In vitro experiment revealed that all the tested acids were found to have direct fungicidal effect on B. cinerea growth. Oxalic acid was the most effective causing total inhibition to the fungal growth. The disease severity on strawberry fruits stored at 0±1°C for 21 days was significantly reduced in all treatments of acids on both tested cultivars. However, Boric acid (40 mM) was, in general, the most effective treatment in reducing disease severity followed by Ascorbic acid (40 mM), especially for artificially inoculated strawberry fruits, while Oxalic acid and Ascorbic acid were the least efficient in reducing disease severity at the lower concentration. The effect of different acid treatments on the activity of oxidative enzymes revealed a correlation between the reduction in disease severity and increase in enzymes activity of polyphenoloxidase (PPO) and peroxidase (POX). However, there was no consistency in the activity of catalase (CAT) in correlation with disease severity. The total phenols concentrations in fruits were significantly increased with all treatments. The free radical scavenging activity analysis in fruits showed a high correlation between the total phenols concentrations and antioxidants scavenging activities in both tested cultivars. The overall conclusion is that the acids under investigation induced a resistance against B. cinerea in fruits during storage and significantly suppressed gray mold severity.

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