Apparatus for detecting climatic conditions favoring the development of scab on fruit trees

Apparatus for detecting the climatic conditions favourable to the development of scab on fruit trees and for indicating when to effect a fungicidal treatment thereof, said apparatus comprising:

• a memory settable into first and second states which correspondingly determine first and second operational states of the apparatus;
• a manually-operable control device for setting said memory into its said first state;
• monitoring device controlled by said memory to operate in accordance with the current state of the apparatus, said monitoring device including:
• temperature and humidity sensors arranged to monitor the ambient temperature and humidity,
• a pulsed signal generator connected to said sensors and arranged to output a first pulsed signal to be counted when the apparatus is in its said first state, and a second pulsed signal to be counted when the apparatus is in its said second state, the frequencies of said first and second pulsed signals being differently related to the ambient temperature and humidity, and
• counter means connected to said pulsed signal generator and operative in the said first state of the apparatus to effect a first count by counting the pulses of said first pulsed signal, and in the said second apparatus state to effect a second count by counting the pulses of said second pulsed signal, the counter means including reset and enable inputs and being arranged upon completion of said first count to set said memory into its second state,
• count enable means connected to the said enable input of the counter means and including a sensor arranged to output an enabling signal in the presence of leaf saturation or surface dampness conditions favouring the development of spores, the count enable means being controlled by said memory such that with the apparatus in its said first state the counter means is enabled to effect said first count only when said enabling signal is present, while when the apparatus is in its second state the counter means is continuously enabled to effect said second count,
• a timer circuit connected to said count enable means and operative in the absence of said enabling signal when the apparatus is in its first state, to time a delay period upon the completion of which said timer circuit is arranged to output a reset signal to the said reset input of the counter means, the reappearance of said enabling signal during the timing of said delay period being arranged to deactivate the timer circuit, and
• output means connected to said monitoring device and operable to provide a visual indication of the progress of the counting being effected by the said counter means.