Thumbnail Image

Anand Agricultural University, Anand

Anand Agricultural University (AAU) was established in 2004 at Anand with the support of the Government of Gujarat, Act No.(Guj 5 of 2004) dated April 29, 2004. Caved out of the erstwhile Gujarat Agricultural University (GAU), the dream institution of Sardar Vallabhbhai Patel and Dr. K. M. Munshi, the AAU was set up to provide support to the farming community in three facets namely education, research and extension activities in Agriculture, Horticulture Engineering, product Processing and Home Science. At present there seven Colleges, seventeen Research Centers and six Extension Education Institute working in nine districts of Gujarat namely Ahmedabad, Anand, Dahod, Kheda, Panchmahal, Vadodara, Mahisagar, Botad and Chhotaudepur AAU's activities have expanded to span newer commodity sectors such as soil health card, bio-diesel, medicinal plants apart from the mandatory ones like rice, maize, tobacco, vegetable crops, fruit crops, forage crops, animal breeding, nutrition and dairy products etc. the core of AAU's operating philosophy however, continues to create the partnership between the rural people and committed academic as the basic for sustainable rural development. In pursuing its various programmes AAU's overall mission is to promote sustainable growth and economic independence in rural society. AAU aims to do this through education, research and extension education. Thus, AAU works towards the empowerment of the farmers.

Browse

20051
Reset filters
Subject: Plant Pathology × Author: KUMARI, HEMLATA × End date: 2005 × Start date: 2005 × Type: Thesis × Thesis Type: M.Sc ×
Reset filters

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    ThesisItemOpen Access
    LEAF BLIGHT OF ONION CAUSED BY Alternaria alternate (Fr.) KEISSLER AND ITS MANAGEMENT BY DIFFERENT FUNGICIDES
    (AAU, Anand, 2005) KUMARI, HEMLATA; PATEL, S. J.
    Onion (Allium cepa L.) is an important cash crop used as vegetable, condiment and medicine. Onion is cultivated throughout the world under an area of 22.81 lakhs hectares with total production of 380.22 lakhs MT. Several factors have been identified which limit the onion production and productivity. Among these, leaf blight caused by Alternaria spp. is an important disease affecting both bulb and seed crop of onion found in India. The disease first appeared in the field as whitish circular to irregular specks, which were less than 1 mm in diameter. These specks developed into a whitish sunken lesion, when the conditions were congenial for the disease development. The typical symptom of this disease is dark purple/ brownish patches with yellow halo and more prevalent on lower leaves. Pathogen was isolated from infected leaves of onion showing typical symptoms of purple or dark brown spots having concentric rings on PDA and Koch's postulates were established for pathogenisity test. The pure culture of isolated pathogen was sent for identification to Indian Type Culture Collection (I.T.C.C), I.A.R.I., New Delhi-110 012 and idenfified as Alternaria alternata (Fr.) Keissler. The study revealed that the fungus produced mycelial growth on PDA which was septate and whitish green in colour when young, later turned light green to dark brown within 10 days and branched irregularly at acute angle. The conidiophores of the fungus were light brown, simple and septate. Conidia were light to dark brown. muriform with 1-5 transverse septa and 0-2 longitudinal septa, variable in size and shape. They were obclavate to oval in shape with rudimentary beak and measured 10.83-59.57 X 5.42-16.25 µm (av. 31.73 x 11.54 µm). Maximum growth of Alternaria alternata was seen on media Potato Dextrose Agar at pH 6.0. Among the nine fungicides tested in vitro, mancozeb (Dithane M-45, 5000 ppm), carboxin + thirum (Cosko, 1500, 3000 and 6000 ppm) and copper oxichloride (Blitox, 5000 ppm) were found significantly superior over the rest of the fungicides as judged by complete inhibition of growth of Alternaria alternata (Fr.) Keissler. Propiconazole (Tilt) was showing reverse effect on the growth of test fungus. As the concentration was increasing, per cent inhibition was decreasing. Total nine fungicides used in field against leaf blight disease of onion were found significantly effective in reducing the disease incidence. Three spray of mancozeb (Dithane M-45, 0.25 %) at 20 days interval was the most effective fungicide followed by metalaxyl + mancozeb (Ridomil MZ, 0.3 %), iprobenfos (Kitazin, 0.1%) and chlorothalonil (Kavach, 0.2%) in managing the leaf blight disease of onion. With regard to yield, significantly highest bulb yield was recorded in the treatment of mancozeb (Dithane M-45, 0.25 %). Tip burning effect on onion leaves was seen by spray of carboxin + thirum (Cosko, 0.3 %). Among the nine insecticides tested in vitro, monocrotophos (Nuvacron, 500 and 1000 ppm) and cypermethrin (CipIon-25, 200 ppm) were found significantly superior over the rest of the insecticides judged by maximum per cent inhibition of growth of A. alternata. Endosulfan acted as nutritive for fungal growth. As the concentration was increasing, fungal radial growth was also increasing. Chemical analysis of healthy and diseased plant / plant parts revealed that the concentration of phenol increased in diseased leaf parts by 1024.25 µg/g than healthy ones and 1060.6125 µg/g in diseased bulb parts than healthy ones. Similarly, the concentration of protein decreased in diseased leaf parts by 0.6123 g/lOOg than healthy ones and 0.4400 g/100g in diseased bulb parts than healthy ones.