Chemical fungicides are effective tools in controlling plant pathogens; however, these chemicals can, on the
other hand, distress the ecosystem. Accordingly, the current research investigates the potentiality of substituting
traditional chemical fungicides by inducing plant resistance against infection with soil-born pathogens i.e.
Sclerotium rolfsii in the presence of mycorrhizae (AMF) as plant inoculants and one of the following amendments:
humic acid, sulphex (a mixture of canola oil and diluted sulphuric acid) and paclobutrazol (ABZ). To attain the
abovementioned objective, a field (mildly infected with S. rolfsii) was cultivated with Helianthus tuberosus (a
perennial plant belongs to the Asteraceae family) for two successive seasons (2014 and 2015) and the abovementioned
treatments were tested for their feasibilities in controlling S. rolfsii infection against the chemical
fungicide “Vitavax-200” either solely or in combinations in a complete randomized block design. Inoculating
plants with AMF or amending soils with either humic acid, Sulphex or ABZ solely increased significantly the
activities of plant defense enzymes by approximately 1.5–2.1 folds higher than the control treatment. These
treatments also improved NPK availability in soil and; hence, increased their contents within plant tubers.
Consequently, these treatments decreased the disease incidence and severity caused by S. rolfsii while improved
shoot biomass and tuber yield. In spite of that, these results stood below the prospective of the fungicide
treatment. The integrated treatments i.e. “humic acid + AMF”, “Sulphex + AMF” and “ABZ + AMF” caused
further significant improvements in both NPK availabilities in soil and plant areal bio-masses. This probably
induced further plant resistance against the investigated soil-borne pathogen while recorded insignificant variations
in disease incidence and severity when compared with the fungicide treatment. Moreover, the integrated
treatments increased the tuber yields beyond those attained for the fungicide treatment. Accordingly, such integrated
strategies can completely substitute the chemical fungicides; thus, minimize their negative impacts on
the ecosystem. |
