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Monitoring Wheat Rust Epidemics With the Landsat-2 Satellite. S. Nagarajan, Tropeninstitut, Justus Liebig-Universitšt, 6300 Giessen, Federal Republic of Germany; G. Seibold(2), J. Kranz(3), E. E. Saari(4), and L. M. Joshi(5). (2)Strahlenzentrum, Justus Liebig-Universitšt, 6300 Giessen, Federal Republic of Germany; (3)Tropeninstitut, Justus Liebig Universitšt, 6300 Giessen, Federal Republic of Germany; (4)Regional Plant Pathologist, CIMMYT, P.O. Box 2453, Bangkok, Thailand; (5)Division of Mycology and Plant Pathology, Indian Agricultural Research Institute, New Delhi-12, India. Phytopathology 74:585-587. Accepted for publication 17 October 1983. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1984. DOI: 10.1094/Phyto-74-585.

In 1978, serious epidemics of yellow rust and leaf rust occurred in the major wheat growing plains of Pakistan while similar areas in adjacent India were free from these diseases. Analysis of Landsat-2 multispectral scanner negatives for April 1977 and 1978 channels 6 (wavelength range 0.7- 0.8 μm) and 7 (wavelength range 0.8- 1.1 μm), that covered both the disease-affected and unaffected areas, revealed that crop plant stress caused by disease can be monitored. Data recorded by channels 6 and 7 during the disease-free years of 1977 and 1978 in India had overlapping values, indicating a similar status of health; while the 1978 wheat crop in Pakistan was seriously diseased and reflected more of the infrared (wavelength range 0.7- 0.8 μm). This difference was due to disease, because soil, crop, and weather conditions were almost identical on both sides of the border. Although channel 7 data showed similar differences, these were not conspicuous. These studies established the possible utility of Landsat-2 in assessing crop health.

Additional keywords: epidemiology.