Background: Cyanobacterium-based silver nanoparticles are considered not only as an efficient nano-nematicide but also as a bio-stimulant material for plant growth. They could be employed as a part of an integrated program for controlling some plant diseases. Results: In this study, silver nanoparticles (Ag-NPs) were biosynthesized from aqueous extract of the cyanobacterium, Nostoc sp. PCC7524. Full characterization of the biosynthesized Ag-NPs was monitored by UV-vis spectroscopy, transmission electron microscopy, X-ray diffraction pattern, Zeta sizer, and Fourier transform infrared spectroscopy. In vitro assay against the root-knot nematode Meloidogyne javanica showed that Ag-NPs significantly decreased egg hatching of M. javanica at different applied concentrations (3, 6, 12, 25, and 50%, v/v). Fifty percent of Ag-NPs induced the highest reduction percent (94.66%). Moreover, Ag-NPs and AgNO 3 significantly increased the percentages of larval mortality of the second-stage juveniles (J 2) with concentration and time-dependent responses. Ag-NPs or AgNO 3 at 2.4 ml/l, 24 h, completely inhibited the growth of J 2 compared to 23% inhibition using aqueous cyanobacterial extract (ACE). In vivo effect of Ag-NPs on faba bean-infected plant under greenhouse conditions was achieved by treating soil with three different concentrations of 1, 2, and 3 ml/kg soil over two consecutive seasons. Ag-NPs significantly reduced root galling from 39.6 to 78.7% and J 2 population in the soils from 32.2% to 86.7% in the 2018 season and from 21.9 to 78.1% and 40.0 to 81.0% in the 2019 season, respectively. Moreover, 3 ml/kg soil of Ag-NP treatment showed statistically comparable effects to that of vydate nematicide but with remarkable enhancement of faba bean growth parameters as compared to those of vydate or AgNO 3 treatments in the two seasons. Conclusions: The considerable in vitro and in vivo nematicidal potential of the cyanobacterium-based Ag-NPs, besides their bio-stimulant effect on plant growth, makes them feasible for the biological control of M. javanica.
Nematicidal activity of heat-sterilizing filtrate culture of Myrothecium verrucaria was evaluated against Meloidogyne incognita in Vitro and the metabolites formulated as granules of M. verrucaria were prepared and tested on sugar beet plants infested with M. incognita comparison with DiTera™ and Rugby 10%G, under greenhouse conditions. Laboratory results showed that sterilized culture filtrate of the fungus M. verrucaria either by syringe or by autoclaving significantly reduced the percentages of egg hatching and increased the percentage of 2 nd stage juveniles (J2) mortality of M. incognita. The most effective reductions of hatching were obtained at 50% concentration with the sterilized filtrate by autoclaving (94.23%), while the most effective reached 96.70% increasing in the percentage of mortality of J2 after 3 days from treating by 50% concentration in case the sterilized filtrate by syringe. Results of greenhouse experiment showed that, all treatments by the prepared fungal formulae of M. verrucaria or DiTera with different rats significantly reduced the number of galls on sugar beet roots and final nematode population (J2) in soil compared with control (nematode only). The higher rate (0.2 g /pot) was achieved the highest reduction in root-galling (86%) with DiTera treatment and the highest reduction in (J2) with fungal formulae treatment (92.2%). Improvement in plant growth parameters were noticed by treatments. Analysis by GC-MS of the fungus metabolites was identified compounds to have antimicrobial and nematicidal activities. The prepared formulae from the Egyptian isolate of M. verrucaria can be used as safety bio-nematicide against M. incognita on sugar beet.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.