Sclerotium rolfsii management in tomato using Aframomum melegueta, Ocimum gratissimum and Cymbopogon citratus

Tomato (Lycopersicon esculentum Mill.) is a popular fruit vegetable in Nigeria but production is low due to diseases, among the various disease problems associated with tomato production is southern blight caused by Sclerotium rolfsii. This study was carried out to evaluate the efficacy of Aframomum melegueta, Ocimum gratissimum and Cymbopogon citratus in vitro and in vivo. Infected tomato stems were obtained from the experimental plots of National Horticultural Research Institute, Nigeria. Cultural and morphological identification of the organism was done with the use of microscope. A. melegueta seeds, fresh leaves of O. gratissimum and C. citratus were used. The experiment was replicated three times, radial growth (mm) was measured for 5 days at an interval of 24 h. The in vivo experiment was conducted using the same extracts in a screen house and the experiment was laid out in triplicates in completely randomised design with the synthetic fungicide as control. Data collected were subjected to analysis of variance and significant means were separated using Fisher’s Least Significant Difference at P ⩽ 0.05. The results showed that the extracts differed significantly (P ⩽ 0.05) in their potential to inhibit the growth of S. rolfsii. The highest reduction (1.27 mm) in radial growth was obtained with 5% O. gratissimum extract while the least (4.63 cm) was recorded with the control. Disease severity and fruit yield varied among the treatments. The highest yield (170.6 g) was obtained on plants treated with 5% O. gratissimum extract and this was comparable with the yield (155.8 g) obtained on plants treated with funguforce.