Ecology, Environment and Conservation Paper

PREVALENCE OF CITRUS CANKER CAUSED BY XANTHOMONAS AXONOPODIS PV.CITRI. IN EASTERN AND NORTHERN REGION OF MADHYA PRADESH, INDIA

Prashant Singh, Prashant Kumar Singh, Shyam Kishor Patel, Sukram Thapa and N. Shivajyothi

Abstract

Bacterial canker is one of the most common citrus diseases, causing widespread losses throughout the citrus growing regions of the world, including India. Madhya Pradesh is one among the leading states in India for citrus production. Therefore, to Keep track of the disease prevalence on lime, lemon, malta, grapefruit, and other citrus fruits, a survey was conducted in eastern (Baghelkhand) and northern (Gird) regions of Madhya Pradesh during the months of February to March 2022. Various crucial data were collected on disease severity (percentage) and disease incidence (percentage). During the survey, disease incidence was recorded from 0% to 40% range, and disease severity from 0% to 37%, with a maximum mean disease incidence (36.5%) and severity (34%), respectively, in Chinor tahsil of Gwalior district and a minimum disease incidence (18%) and severity (17.3%) in Satna district of Madhya Pradesh. Disease samples of Xanthomonas axonopodis pv.citri were collected from various villages in the chosen district during the survey (Turari, Bhanduli, Khohar, Ambha, and Panihar). After three days of purification, all five isolates showed a light yellow to yellow colour, a mucoid surface, and a circular colony with a diameter of 4 to 5.5 mm. The biochemical characteristics of bacterial isolates subjected to various biochemical tests, including the catalase test, KOH solubility test, H2S production, and Gram reaction, were studied. All isolates were positive in catalase, KOH solubility, and H2S production tests, but negative in Gram’s reaction. The virulence behaviour of the isolates, namely Xacl, Xac2, Xac3, Xac4, and Xac5, was diagnosed during the pathogenicity test by spraying the isolate suspension on the citrus plant. Symptoms appear 12-17 days after inoculation with a different isolate. Lesions appear on the leaf’s bottom surface as small, translucent, round spots. A yellow halo surrounded the lesions. Isolate Xac3 develops water-soaked lesions on the leaves 12 days after inoculation. Other isolates, such as Xac4, had low virulence, with symptoms showing up after16 days. Xac1, Xac2, and Xac5 were all partially virulent isolates.