Agriculture Reference
In-Depth Information
Chapter 11
Site-Specifi c Sensing for Fungicide Spraying
Eiko Thiessen and Hermann J. Heege
Abstract
Especially in humid moderate climates, high yields require the application
of fungicides. Its site-specifi c application based on the biomass of crops is state of
the art. Yet this technique does not take into account that fungal infections in most
cases start and spread out from small, initial spots within a fi eld. So a sensing tech-
nique to detect these initially small infected spots would be of great importance for
saving fungicides, for reducing damage to crops as well as to the environment and
for allowing higher driving speeds in uninfected areas. Refl ectance indices of visi-
ble and near-infrared light as well as indices of fl uorescent light are candidates for
detecting these spots.
Detecting the fungi in early stages of infection (= latency stage) can be important
for a successful treatment, because stopping the infection after this time gets more
diffi cult. In this latency stage, the diseases might not yet be visible by human eyes.
Fungal diseases often change the physiological state of plants either by means of the
photosynthesis or by the formation of secondary metabolites like phenols. These
changes can be detected in the smartest way by optical sensing. Hereby fl uores-
cence is a sensitive method with the potential of detecting changes before infections
are visible by human eyes.
Keywords
Fluorescence • Fungal infection • Optical sensing • Site-specifi c
