Study of Root–Knot Disease on Vegetables in Katsina Metropolis, Nigeria

The survey was conducted to assess the incidence and frequency of occurrence of root-knot disease on vegetables in and around Katsina metropolis (Kofar Marusa, Kofar Durbi and Kofar Sauri) Nigeria. The study showed that the areas were infested with root-knot disease. Highest frequency of disease was found in Kofar Marusa followed by Kofar Durbi and Kofar Sauri and overall incidence in all the areas was 40.6%. The intensity of disease in different fields and on different vegetables showed wide variations. Root-knot gall index/egg mass index ranged 2–5/2–5. Tomato and pumpkin were the most infected crops in the areas as 60%, 57.1% respectively, followed by carrot, lettuce, cabbage and spinach as 44.4%, 37.5%, 30.0%, 28.6% respectively. Onion had less infection (22.2%). M. incognita and M. javanica were identified to be present in the areas associated with vegetables. The species were found in single populations. M. incognita (62.5%) was the dominant species over M. javanica (37.5%).