A weather-based scheme to advise on limited chemical control of groundnut leaf spot diseases in India

Butler, D.R. and Wadia, K.D.R. and Reddy, R.K. and Das, N.D. and Johnson, B. and et al, . (2000) A weather-based scheme to advise on limited chemical control of groundnut leaf spot diseases in India. Experimental Agriculture, 36 (4). pp. 469-478.

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Infection of groundnuts by pathogens causing early and late leaf spot diseases (Cercospora arachidicola [Mycosphaerella arachidis] and Phaeoisariopsis personata [M. berkeleyi], respectively) is strongly affected by accumulated daily leaf wetness periods and, in the rainy season, temperature is unlikely to severely limit infection. Earlier work relating patterns of leaf wetness to infection, was used to define a daily Wetness Index (WI) which was compared with infection on inoculated plants exposed in the crop for periods of 7 d. Infection was only severe when the 7-d WI total exceeded a value of 2.3. The proportion of leaves with one or more lesions on the main stem was used to assess the amount of inoculum in the crop. When the proportion of diseased leaves exceeded 10% and the WI total exceeded the threshold, application of a fungicide was advised. Successive sprays were separated by at least 14 d and a maximum of three sprays were applied in the growing season. Field trials showed that three sprays gave limited benefit where the disease pressure was severe, but substantial increases in pod and haulm yield were possible with only one or two fungicide applications in locations with less disease pressure

Item Type: Article
Author Affiliation: International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) Patancheru, 502 324, Andhra Pradesh, India
Subjects: Atmosperic Science > Climatology
Plant Protection > Pesticides
Plant Protection > Pests
Divisions: Groundnut
Depositing User: Mr B Krishnamurthy
Date Deposited: 06 Jun 2011 08:46
Last Modified: 06 Jun 2011 08:46
URI: http://eprints.icrisat.ac.in/id/eprint/2111

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