Performance of induced resistance chemicals (IRCs)‎ on olive transplants root rot disease under greenhouse conditions

الملخص EN

Root rot of olive transplants is a severe disease caused by several soil borne fungi recording high loss in growth and transplants production in nurseries.

Benzoic acid, Sorbic acid, Salicylic acid, Propionic acid, Potassium sorbate, Potassium silicate, and Hydroqunion as Induced Resistant Chemicals (IRCs) were tested against linear growth of pathogenic fungal isolates causing root rot of olive transplants i.e., Macrophomina phaseolina, Botryodiplodia theobromae, Fusarium solani and Rhizoctonia solani.

The tested concentrations of Induced Resistance Chemicals (IRCs) significantly reduced the mycelium growth of tested fungi.

Benzoic acid, Sorbic acid, Propionic acid and Salicylic acid with 25mM concentration recorded and 100% growth reduction of tested fungi.

All tested concentrations of Propionic acid completely inhibited the linear growth of all tested fungi.

Also complete inhibition of linear growth was obtained with Benzoic acid, Sorbic acid, Salicylic acid at concentrations of 10, 15 and 25 mM with all tested fungi except that B.

theobromae while other treatments showed moderate effects.

The efficiency of four Induced Resistance Chemicals (IRCs) on disease incidence and severity was carried, under greenhouse conditions during 2019 and 2020 seasons at faculty of agriculture farm, Fayoum.

Results reveal that, for 2019 growing season, the most effective treatments are Sorbic acid, Propionic acid and Salicylic acid which suppressed the disease incidence by 80.45, 91.30 & 82.61 % and disease severity by 85.13, 86.57 & 83.98 % respectively.

Meanwhile, Benzoic acid showed moderate effect.

The same trend was observed during 2020 growing season.

All tested chemicals significantly increase plant growth parameters i.e., plant height (cm), fresh and dry weights (gm) in transplants grown in infested soil with tested pathogenic fungi comparing with untreated transplants.

Results of the present study could suggest that soil drench with Induced Resistance Chemicals (IRCs) can be used as a safe control measure of the disease on olive transplants and as a stimulant of vegetative growth parameters.