Apparatus for detecting climatic conditions favoring the development of

Abstract

For an infestation of scab to develop through its initial stages requires the presence of prolonged periods of leaf surface wetness to enable the spores to germinate. Apparatus is provided which monitors the ambient temperature and humidity to detect the occurrence of periods of leaf wetness sufficient to permit the initial development of an infestation. When the occurrence of such a period of wetness is detected, the apparatus changes its operating state to indicate the progress of the infestation through its secondary stages, this progress being dependent on the ambient temperature but not the wetness of the leaves. The apparatus follows the progress of the infestation by means of a monitoring device which generates a pulsed signal whose frequency is dependent on the ambient temperature and humidity, the pulses of this signal being then counted in counter means and selectively displayed on a display. A leaf wetness sensor is arranged to inhibit the counter means during the initial infestation stage except in the presence of conditions favoring spore development.