Tikka Disease of Groundnut PDF

Tikka Disease of Groundnut Tikka disease of groundnut is a disease also called Leaf spot disease. The causal organism of tikka disease belongs to the genus Cercospora and mainly includes the two species (Cercospora arachidicola and Cercospora personata). Tikka disease cause epidemics in all the gro...

Tikka Disease of Groundnut Tikka disease of groundnut is a disease also called Leaf spot disease. The causal organism of tikka disease belongs to the genus Cercospora and mainly includes the two species (Cercospora arachidicola and Cercospora personata). Tikka disease cause epidemics in all the groundnut crop growing countries, including the United States, China, India etc. and according to the survey, it can decrease the crop yield by approximately 22%. Cercospora arachidicola causes Early leaf spot, which is distinguished by the appearance of brown spots with a yellow halo that are few in number and small in size. Cercospora personata causes Late leaf spot, which is identified by the appearance of black spots that are common, more in number and potentially more damaging. Causal Organism of Tikka Disease The causative agent of tikka disease of groundnut belongs to the genus Cercospora and typically includes two different species, namely Cercospora arachidicola and Cercospora personata. Distribution: Widespread in tropical countries where the groundnut crop production is more. Morphological Features of Cercospora arachidicola and Cercospora personata Cercospora arachidicola and Cercospora personata show the following morphological features Mycelium: Cercospora arachidicola appears dark brown in colour and grows intracellularly in the plant cell. Cercospora personata appears brown-black in colour and first grows intercellularly and later intracellularly. Haustoria: Cercospora arachidicola lacks haustoria. Cercospora personata contains branched haustoria. Conidiophore: Cercospora arachidicola consists of continuous, unbranched, yellowish- brown, geniculated and septate (1-2 septa present) conidiophore. It is 22-44 µ long and 3-5 µ wide. Cercospora personata consists of continuous, unbranched, light brown in colour, geniculated and aseptate conidiophore. It is 25-54 µ long and 5-8 µ wide. Conidia: Cercospora arachidicola consists of long, cylindrical, hyaline (Pale yellow in colour) conidia. It is 38-108 µ and 6-8 µ wide. The shape of conidia truncates at the base and sub truncates at the apex. Conidia of Cercospora arachidicola are septate, and around 1-12 septa are present. Cercospora personata consists of short, cylindrical conidia. It is 18-60 µ and 6-11 µ wide. The shape of conidia is rounded at one end and tapered on the  other end. Conidia of Cercospora personata is septate, and around 3-4 septa are present. Symptoms of Tikka Disease of Groundnut 1. Cercospora arachidicola cause early leaf spot infection, which includes symptoms like brown-coloured round or oval spots. Yellow halo also appears around the spots in an irregular fashion. 2. Cercospora personata cause late leaf spot infection, which includes symptoms like the appearance of the large and dark black-coloured spots on the leaves, stems, seeds and shells of the groundnut. Control Measures Management of early tikka disease of groundnut: The early infections of tikka disease can be managed by the following ways, which includes: Crop rotation Eradication of infected plants by burning or burying them in deep pits. Pruning can also be done with the help of pruning scissors by removing the infected parts of the plant. The seeds of groundnut that are within the shells can be disinfected with sulphuric acid, and those are without the shell can be treated for half an hour with 0.5% of copper sulphate solution. Raw seeds after dressing with Agrosan GN can also reduce the chances of infection. Management of late tikka disease of groundnut: The late infections of tikka disease can be only managed by the use of effective fungicides like Bordeaux mixture as a spray. Infected Leaf of Arachis hypogea T. S of infected leaf showing conidia Conidiophore and conidia