In vitro evaluation of some plant extracts for the management of Alternaria solani causing early blight of tomato

Abstract

Tomato early blight caused by Alternaria solani is an economically important disease causing threat to tomato cultivation wherever it’s grown. This study evaluated the effect of three different plant extracts Neem (Azadirachta indica), Garlic (Allium sativa) and Ginger (Zingiber officinale) against Alternaria solani the causative agent of early blight of tomato. The experiment was 3 × 5 factorial pitted in a Completely Randomized Design (CRD). The treatment were garlic, ginger and neem extracts at four different concentration (25%, 50%, 75% and 100%) control and check which were replicated three times. Data were recorded on mycelial growth of the fungus and percent growth inhibition of the extracts against A. solani. The result from the study revealed that neem extract had the least mycelial growth as well as higher percent growth inhibition compared to other treatments, followed by garlic throughout the inoculation periods. Plant extracts at 75% and 100% had the least mycelial growth compared to the control. Plant extracts at lower concentration of 25 and 50% exhibited the least percent growth inhibition compared to the control. Neem and garlic extracts at 75% and 100% concentration significantly inhibited the growth of the fungus and could therefore be recommended for further studies in the screen house and field to evaluate their efficacies against early blight of tomato under field condition.

Keywords: Plant extract, mycelial growth, mycelial growth inhibition, neem, garlic, ginger