Abstract:
Synthetic fungicides are currently used as primary means for the control of plant
disease. Besides, the inherent hazards and negative public perceptions about the
synthetic chemicals, using of essential oils as novel alternative inhibitory agents
against phytopathogens. Essential oils are complex mixtures of hydrocarbons and
their oxygenated derivatives arising from two different isoprenoid pathways. The
antimicrobial activity of essential oils reduces hyphal growth and also induces lysis and
cytoplasmic evacuation in fungi. With this background, The antifungal properties of
6Eos, includes citronella (Cymbopogon nardus), lemon grass (Cymbopogon citratus),
clove (Syzygium aromaticum), thulsi (Ocimum tenuiflorum), castor (Ricinus communis)
and Eucalyptus (Eucalyptus globules) oil were screened. The oils are tested in liquid
bioassay (Poison food technique) for confirmation. The test oils at 0.1- 1.00 percent
(v/v) were prepared and added to the flasks separately. Tween 80 at 0.01 percent was
used as a surfactant to disperse the oil. The contents were thoroughly mixed by
placing the flasks on a shaker at 28±2˚C. P. aphanidermatum (9 mm) culture was
aseptically introduced into flasks. The inhibitory effect of oils showed dose-dependent
activity on the tested fungus. Based on the MIC Values, Eucalyptus, clove, thulsi and
citronella were the most effective. With regard to the essential oils screened,
Eucalyptus oil at (0.1 percent) was found to be superior to other oils tested against P.
aphanidermatum (isolate Pa5). We observed MIC minimum inhibitory concentration
in In-vitro assay. Mode of action involves induction of changes in cell wall composition
plasma membrane disruption, mitochondrial structure disorganization. This study
warrants further research into the practical use of EOs for the control of important
phytopathogens in intensive Agriculture
