The potential of optical canopy measurement for targeted control of field crop diseases.

There is increasing pressure to reduce the use of pesticides in modern crop production to decrease the environmental impact of current practice and to lower production costs. It is therefore imperative that sprays are only applied when and where needed. Since diseases in fields are frequently patchy, sprays may be applied unnecessarily to disease-free areas.

Understanding Puccinia striiformis West. epidemics on winter wheat.

Yellow rust epidemics, caused by Puccinia striiformis West., often arise in wheat field as infection focus of a few decimetres of diameter, including some sporulating lesions on a few plants. Under appropriate environmental conditions such as high relative humidity and temperatures between 2 and 20 degrees C, those initial foci may grow rapidly and initiate new foci elsewhere in the field.