Influence of Environmental Conditions on the Chrysanthemum Leaf Yellow Spot - Measurement of the Leaf Yellow Spot at Early Stage -

In recent years, yellow spots appear on the leaf of chrysanthemums in many species, which brought commercial problems. The purpose of this study is to examine the measurement of the spot in order to make the influence of environmental conditions clear. Image instrumentation with transmitted light made possible to measure the spot at early stage, which was difficult for reflected light. The method is used the gap of the light quantity between the spot and others. It is involved in chlorophylls and the use of the suitable light color make measuring easy. The portable device using this method was produced experimentally and leaf yellow spot was measured with this device, which brought the basic data, the state get worse with time and the relationship between the spot and environmental conditions.