Isolation and characterization of bacterial spot disease of citrus through biochemical approaches and its control measures

Abstract

Citrus bacterial spot disease is caused by Xanthomonas campestris pv. citrumelo, which produced unsightly blemishes on leaves and stems of nursery plants and reduce its market value. The present study was done to identify the pathogen from citrus infected leaves, and find out its biological control. Different biochemical tests including gram staining, motility, Simmons citrate, urease, catalase, potassium hydroxide, Triple sugar iron, Kligler iron agar, MacConkey agar, Kovacs oxidase tests showed positive response against the isolated bacteria. All biochemical test results ensured that, the isolated bacteria was gram negative. Chloramphenicol (30 mcg) revealed the highest antibiotic sensitivity with 32±0.5 mm diameter of zone of inhibition against the isolated bacteria. The raw extract of Allium sativum showed highest antibacterial activity with 16.0±0.5 mm diameter against the isolated bacteria. The study will be helpful to confirm the efficacy of these antibiotics and plant extracts to make biological control of the disease.