Biological investigations on the role of hydrogel formulations containing bioactive natural agents against some common phytopathogens of Phaseolus vulgaris L. and seed germination

Recent scientific research have manipulated the use of hydrogel in seed coating technology based on synthetic and chemical additives. The current study has been carried out to evaluate the biological activity of new seed coating formulations containing hydrogel based on natural substances or beneficial microorganisms on seed germination and controlling some common diseases of Phaseolus vulgaris L. New formulations have been prepared as single mixtures of hydrogel with the following bioactive substances: i) oregano Essential Oil (org EO); ii) Ornithine Lipid (OL); and two microorganisms i) Burkholderia gladioli and ii) Trichoderma harzianum T22. Results revealed that, the hydrogel formulation based org EO showed the highest significant activity against the majority of tested phytopathogens in a dose dependent manner. Regarding the antagonistic microbial activity, results showed that hydrogel formulations based T. harzianum T22 and B. gladioli were able to significantly reduce the growth of the majority of tested phytopathogens. In addition, the highest significant percentage of seed germination has been achieved using the formulations of B. gladioli and org EO. Regarding the disease incidence suppression assay, results explicated that org EO and OL were able to significantly inhibit the fungal disease incidence on P. vulgaris seeds steadily depending on the tested concentrations. In conclusion, the use of natural bioactive substances in hydrogel formulation would greatly reduce dependence on chemical pesticides and hence decreasing the environmental pollution and eventual harmful effects on plant, animal and human health.