Copyright © 2013 IJAIR, All right reserved 125 International Journal of Agriculture Innovations and Research Volume 2, Issue 1, ISSN (Online) 2319-1473 Soil Fertility and Potato Pest Spectrum in Nilgiris K. Manorama Central Potato Research Station, Muthorai, The Nilgiris, Tamil Nadu – 643004 Email: kmano1000@yahoo.com T. A. Joseph Central Potato Research Station, Muthorai, The Nilgiris, Tamil Nadu – 643004 G. Ravichandran Central Potato Research Station, Muthorai, The Nilgiris, Tamil Nadu – 643004 R. Muthuraj Central Potato Research Station, Muthorai, The Nilgiris, Tamil Nadu – 643004 R. Umamaheswari Central Potato Research Station, Muthorai, The Nilgiris, Tamil Nadu – 643004 B. P. Singh Central Potato Research Institute, Shimla, Himachal Pradesh – 171001 N. Somasekhar Directorate of Rice Research, Rajendra Nagar, Hyderabad - 500030 Abstract – A survey was undertaken in Nilgiri district of Tamil Nadu State in India during the year 2008 to witness the status of potato cultivation as well as the disease and pest spectrum and a comparison was made with the status during 2011 by conducting another sample survey. The principal conclusions of the survey are: The area under potato cultivation in Nilgiris is decreasing year after year. Late blight is the number one problem and cyst nematodes are spread in almost all the areas of potato cultivation. The available nitrogen content of the soils is medium to low and that of phosphorus is low to medium. Potassium is available in plenty. Soils with lower pH and high nitrogen content recorded more PCN (potato cyst nematodes) populations. Inclusion of cabbage in rotation recorded no change in soil pH, lower accumulation of phosphorus and lower PCN population. During the last five years, the average increase in PCN population in entire Nilgiris is 36 per cent. The increase is more spectacular in Kundah (50%) followed by Coonoor (41%) and Kotagiri (34%) taluks and the rate of increase in Ooty area is low (20%) because of the high initial population. There is advancement in the date of first appearance of late blight disease by 10 days (i.e., from 5 th October to 25 th September) especially during autumn season due to change in rainfall pattern and also temperature. Keywords – Late Blight, PCN, Pest and Disease Spectrum, Potato Cultivation. I. INTRODUCTION Generation of statistically valid data on current status of management practices, severity of disease and pest spectrum and on use of quality seed material can be a good contribution towards a sustainable crop production. This data can assist in identification of lacuna in crop production, plant protection and input use and thereby helpful in developing strategies to improve seed health, pesticide minimization and to make use of improved cultural practices. Initially, the founder of present day Udhagamandalam, Mr. John Sullivan introduced potato to Nilgiris (Tamil Nadu state) in 1822 A.D. The potato cultivation in this region picked up well during 1830’s to produce up to an average of about 15 tonnes per ha. The records show that up to 125 hectares of potato was annually cultivated by 1845, which increased to about 300 hectares in 1875. Further, the British settlements in and around Ootacamund town and the mild climatic conditions prevalent throughout the year in these hills for raising more crops per year, enhanced the potato cultivation in this hilly district. The then Imperial Government established a Potato Experimental Station at the village Nanjanad in the year 1917, as the Government gardens had limited area for seed potato production purposes to supply to the increasing demands. Moreover, due to the demands from Colombo, Bombay, Calcutta and other places the area under potato in the Nilgiris has been increasing considerably since 1910 onwards. Further, due to the world wars I and II, the area under potato cultivation increased substantially and it reached a peak of 10,000 ha during 1944. With the establishment of Central Potato Research Station in 1957, the potato production in the Nilgiris has gained a new momentum. Though there was a setback in potato area during 1961 due to the attack of late blight, it again started rising with the introduction of new varieties and suitable management practices. However, with the introduction of premium price for tea due to its export opportunities, most of the area under annual crops has been converted into tea gardens and a very meager area of 3000 ha is under potato crop. In view of the above situation, it was felt necessary to study the present position of potato cultivation, its problems and prospects and to design strategies for extending the potato growing area of Nilgiris. As a sequel to the initial survey conducted during 2008, another quick survey was also found necessary to compare the potato growing situation in a period of five years. The main objectives of the survey were 1. To assess the status of potato cultivation in Nilgiri area of Tamil Nadu 2. To evaluate the impact of management practices on soil fertility status, disease and pest spectrum 3. To design strategies for extending potato area in Nilgiris region II. MATERIALS AND METHODS The Nilgiris district comprises of six taluks viz Udhagamandalam, Kundah, Coonoor, Kotagiri, Gudalur and Pandalur. These taluks are divided in to four Panchayat Unions viz., Udhagamandalam, Coonoor, Kotagiri and Gudalur besides two Municipalities, Manuscript Processing Details (dd/mm/yyyy) : Received : 16/08/2013 | Accepted on : 27/08/2013 | Published : 31/08/2013