تقويم فاعلية الخميرة Kluyveromyces marxianus و حامض السالسلك في مكافحة العفن الأخضر في البرتقال

Abstract EN

This study has been conducted to evaluate the efficacy of the yeast Kluyveromyces marxianus and salicylic acid separately or in combination against green mold of orange fruits caused by Penicillium digitatum4 K.

marxianus showed high efficacy as a biological agent against P.digitatum on PDA with 100 % inhibition at 106 cells / ml.

In addition, salicylic acid in both concentrations 1000 and 500 ppm inhibited P.digitatum growth at 94.3 %, compared to 0.0 % in control.

K.

marxianus suspension at 106 cells / ml and its filtrate inhibited spores germination of P.digitatum completely.

The percentage of spore's germination in liquid PDB containing 100 ppm salicylic acid was found to be 2.3 %, compared to 96.6 % in control.

The average lengths of germ tube in the yeast suspension, yeast filtrate and salicylic acid were found 0.0, 0.0 and 11.2 μm respectively compared to 21.2 μm in control.

A combination of K.

marxianus and salicylic acid Showed higher efficiency in controlling green mold on wounded orange fruits, where it has completely prevented the disease incidence after three days of incubation at 25 ± 2c.

compared with yeast or salicylic acid separately4 Fruits treatment with combination of salicylic acid and K.

marxianus 24 hours before inoculation with P.digitatum has been found more efficient than salicylic acid and K.

marxianus individually in stimulating resistance in the fruits.

The activity of peroxidase (POD) in fruits peel was 5883 unit / s / mg after 96 hours of treatment, while the activity of peroxidase reached in salicylic acid or K.

marxianus to 5132 and 4544 units / s / mg respectively, compared with 3193 and 3380 units / s / mg in control treatments (with pathogen or without pathogen) respectively.