ISHS Acta Horticulturae 130: XII International Symposium on Fruit Tree Virus Diseases
X-DISEASE IN NECTARINE ASSESSMENT BY AERIAL PHOTOGRAPHY. |
| Authors: | L.D. Lathrop, L.B. Forer, D. Bingaman, R.F. Stouffér |
| Abstract:
The detection and assessment of X-disease and other orchard diseases with non-uniform, scattered distribution by traditional ground survey methods is very labor intensive and costly. In 1980, an 80-acre nectarine orchard with scattered trees expressing symptoms of X-disease was selected to compare aerial photographic and ground survey assessment methods. Major considerations evaluated in the study were the relative detection sensitivity and the cost effectiveness of the two methods. The aerial photography was performed by the Pennsylvania Department of Transportation, using infrared film in a large format camera which resulted in 1:6000 scale imagery. The photointerpretation and ground assessment was done by the authors. Degree of symptom expression was catergorized as slight (less than ½ scaffold effected), moderate ( 1 entire scaffold affected) or severe ( several scaffold affected). The results indicated that treed expredding symptoms in the moderate or severe categories could be accurately detected with the remote sensing techniques employed. The relative level of detection and cost effectiveness of the two methods will be discussed. | |
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