Abstract
Arthrobotrys oligospora is a nematode-trapping fungus and one of the most extensively researched biological control agents of plant-parasitic nematodes. Urea and composted organic matter (COM) may also control nematodes by making rhizospheric environment more favorable to beneficial microbes and also boosted the plant growth improvement. Thus, combining A. oligospora with urea and COM may improve nematode biocontrol. For this. an in vitro experiment was performed with three replicates of each parameter and repeated thrice. Inoculation with M. incognita in culture plates revealed that the fungus creates adhesive traps comprised of hyphae loops within 24 h. However, maximal capture was observed after 7 days of incubation. Furthermore, the A. oligospora culture filtrate was highly poisonous to the nematodes. Green house trial was conducted complete randomized block design with three replicates of each treatment, including the control and inoculated control pots. The plants treated with A. oligospora alone or in combination with urea and COM showed improved growth, yield and biochemical characteristics, when compared to M. incognita inoculated plants. Antioxidant enzyme activity (POD, SOD, CAT and PAL) was substantially increased in the plants treated with A. oligospora in combination with urea and COM. Maximum and significant decrease in number of gall (86.89%), size of gall (76.52%), number of egg masses (88.86%) and disease index were observed when fungus was used in combination with COM. Histological examination showed that the presence of A. oligopsora reduced nematode penetration and feeding site when compared to roots infected with only M. incognita, which show breakdown of the vascular bundle due to nematode feeding. These findings imply that combining A. oligospora with urea and COM has the ability to promote plant resilience as well as more trap formation by fungus resulted in prevent M. incognita infection and serve as an environmentally safe alternative to chemical nematicides.