ANTIFUNGAL ACTIVITY OF SOME PLANT ESSENTIAL OILS AGAINST FOUR PATHOTYPES OF Ascochyta rabiei (PASS.) LABR.

Abstract

This study was carried out to determine the antifungal activity of mint (Mentha piperita L.), thyme (Thymus vulgaris L.) and eucalyptus (Eucalyptus citriodora Hook.) essential oils against 4 different pathotypes of chickpea blight (Ascochyta rabiei) under in-vitro conditions. The antifungal activity assay was performed in 100 mm petri dishes containing 20 mL Potato-Dextrose-Agar (PDA) media. Essential oils were added to petri dishes containing autoclaved PDA medium in doses of 0.125, 0.25, 0.5, 1 and 2 mu L mL(-1). 5 mm diameter fungal discs were placed in the middle of petri dishes. PDA medium free of essential oils as negative control and as a positive control PDA media containing commercial fungicide %25.2 Boscalid+%12.8 Pyraclostrobin (BASF company) were used. Petri dishes sealed with para-film were incubated for 14 days at 22 +/- 1 degrees C. The experiment was conducted in a randomized plot design with three replications. Measurements were made after completion of the incubation period and percent inhibition of mycelial growth was determined. It was deteimined that mint essential oil completely inhibited mycelium growth of pathotype I, II and IV, by 100% and the effect was fungicidal at the positive control. The dose of 2 mu L mL(-1) and positive control inhibited mycelium growth of pathotype III, by 81.3% and 82.9% respectively. It was found that thyme essential oil completely inhibited mycelium growth of all pathotypes at the dose of 2 mu L mL(-1) and positive control inhibited mycelium growth of pathotypes I and III, by 100% and the effects was fungicidal. It was seen that eucalyptus essential oil completely inhibited mycelium growth of pathotypes II and. IV, by 100% and this effect was fungicidal at the positive control, The dose of 2 mu L mL(-1) and positive control had an effect of 84.9% and 84.1% against pathotype 1, 84,1% and 83.7% against pathotype III, respectively.