The failure to detect damaged trees harboring pine wilt disease insect vectors is one of the main reasons for lack of success in the control of pine wilt disease (PWD). Aerial surveys to detect wiltaffected trees, i.e. those with discolored foliage, has been proven to be a reliable disease survey technique and as such many governments in Japan have already adopted such methods. This conventional method of aerial survey and following the treatment to detect trees, however, suffer from some technical problems such as insufficient flight time for a detailed survey, the ambiguity of foliage coloration, and the imprecise location of the spotted trees causes difficulties in locating them from the ground. To overcome these problems we introduced using nearinfrared color films. Recent progress in such technology enables us to readily obtain an orthorectified aerial photograph that can provide the exact location (latitude/altitude) of any point. Properly processed nearinfrared photos enhance foliage discoloration and make it more distinct than that in natural color photographs. With the photographs, we can carefully search for the discolored trees in the office without flighttime restrictions. Recognition of trees with foliage discoloration is highly accurate and can be done by personnel with minimal training, however, detection is not 100 % precise because of some problems such as the invisibility of shaded trees from above. The photographs may be electronically reproduced and displayed on a computer monitor. We have developed such a software with which we can designate the target trees and obtain their coordinates on an image file shown on the monitor. The location data for the target trees with the background image of the aerial photograph can be transferred to a palmtop computer with a builtin GPS receiver and the other original software will produce a graphical navigation system for ground approach of the target trees. Using the palmtop computer we can check and edit the data of the target trees on site, and the updated data can be transferred back to the host computer. A consecutive system from detecting the trees to be treated to easy access for disposal and management of the individual tree data will be provided by making good use of the latest technology on aerial photography. This will bring an extensive improvement in control operations against PWD.
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