EFFECT OF SOME ESSENTIAL OILS ON THE GROWTH AND DEVELOPMENT OF FRUIT ROT OF LEMON CAUSED BY ASPERGILLUS NIGER UNDER IN-VITRO CONDITIONS

Abstract

It is common observations that during storage, transportation and marketing fruits and vegetables suffer from many postharvest diseases. Generally the diseases are controlled by applying different chemicals in the form of fungicides. On the other hand, these fungicides are also hazardous for health and disturb the equilibrium of the natural environment. In this regard, researchers have found that certain plant essential oils not only keep away the insects but also show fungicidal actions against some plant pathogens. The aim of current investigation is to find out some suitable and effective essential oils against the growth fruit rot of lemon caused by Aspergillus niger under in-vitro conditions. For this purpose, pathogenicity test against A. niger was performed. The antifungal components of some essential oils like clove, tarpin, neem, castor, chamomile, and rose oil were carried out at different doses i.e. 50 µl and 100µl to find out their effectiveness against A. niger. The results showed that, high severity of disease was determined through the cut method of inoculation as compared to the injection method. Minimum colony growth (1.11% and 0.55%) was examined when plates treated with clove oil at the dosage of 50µl and 100µl followed by tarpin oil (42.22% and 38.89%), neem oil (42.96% and 41.11%), castor oil (52.96% and 50.00%) and chamomile oil (71.85% and 67.77%) respectively. In comparison to control (100%), maximum growth (91.85% and 89.62%) was observed when treated with rose oil at the dosage of 50µl and 100µl. When the inoculated lemon fruits were treated with aqueous solution of essential oils, it was observed that minimum rotting (12.53%) was recorded for clove oil followed by neem oil (13.30%), tarpin oil (13.42%), rose oil (14.27%), castor oil (15.16%) and chamomile oil (17.25%), respectively as compared to control (23.37%). On the basis of present investigation it was concluded that clove oil is highly effective against linear colony growth of A. niger under in-vitro conditions.