The Impact of Wilt Disease on Oil Yield and Quality of Two Cultivars of Rose-Scented Geranium (Pelargonium Species)

Abstract

The impact of wilt disease caused by Fusarium oxysporum var. redolens (Wollenweb.) Gordon, on plant mortality, yield and quality of oils of two rose-scented geranium (Pelargonium species) cultivars was investigated under semi-arid tropical climatic conditions. Wilt disease resulted in plant mortality of 2.6–72.2% (average 19.3%) in one year old plantation and 0-18.0% (average 4.2%) in three months old plantation. Diseased plants recorded biomass yield reductions of 83.1–88.2% in cultivar I, and 73.6–84.3% in cultivar II and oil yield reductions of 87.1% in cultivar I and 69.1% in cultivar II in comparison to healthy plants. Healthy plants of both the cultivars possessed greater concentrations of linalool and geraniol, while the diseased plants had higher contents of rose oxides, isomenthone, citronellol, citronellyl formate and β-caryophyllene in their oils. Healthy and diseased plants of the two cultivars exhibited trend reversals in respect of components such as geranyl formate, citronellyl acetate, geranyl acetate, 10-epi-γ-eudesmol, citronellyl tiglate and geranyl tiglate.