초록 ▼

An infestation of Peronosporales on plant leaves will only fully develop if the leaves experience a period of wetness of a duration sufficient to allow the penetration of zoospores into the stomata of the leaves. The duration of this period is temperature dependent. Apparatus is provided which inclu

An infestation of Peronosporales on plant leaves will only fully develop if the leaves experience a period of wetness of a duration sufficient to allow the penetration of zoospores into the stomata of the leaves. The duration of this period is temperature dependent. Apparatus is provided which includes a pulse generator arranged to generate pulses at a rate dependent on the ambient temperature, a signal gate controlled by a leaf wetness sensor to pass the pulses output from the generator only when the leaves are sufficiently wet to favor penetration of the zoospores, and a counter arranged to count the pulses passed by the gate to time a period the duration of which varies with temperature. Upon completion of timing, the counter outputs an infestation signal which causes a monitor counter to start counting the pulses output from the pulse generator whereby to provide an indication of the subsequent advance of the infestation. Successively generated infestation signals are arranged to cause successive monitor counters to start counting thereby enabling several overlapping infestations to be followed.

대표청구항 ▼

Apparatus for detecting climatic conditions favourable to the development of Peronosporales on plant leaves and for indicating the optimum time for effecting fungicidal treatment thereof, said apparatus comprising: sensor means for detecting conditions corresponding to a saturation or superficial da

Apparatus for detecting climatic conditions favourable to the development of Peronosporales on plant leaves and for indicating the optimum time for effecting fungicidal treatment thereof, said apparatus comprising: sensor means for detecting conditions corresponding to a saturation or superficial dampness of plant leaves sufficient to allow the development of zoospores; timer means connected to the sensor means and operative to output an ‘infestation’signal indicative of the occurrence of a Peronosporales infestation if the said conditions of saturation or of surface dampness of the leaves persist for a time period sufficient for the penetration of the zoospores into the stomata of the leaves, said timer means being so arranged that the duration of the time period timed thereby is a function of the ambient temperature; auxiliary timing means operatively interconnected with said timer means and responsive to the generation of a said infestation signal to time a delay period during which the output of a further infestation signal is prevented, the timer means at the end of said delay period being arranged to be in a state ready to repeat its timing function for a further Peronosporales infestation; and monitoring means responsive to each said infestation signal to monitor the speed of advance of the Peronosporales infestation indicated thereby as a function of the temperature and the humidity of the air, said monitoring means comprising a temperature sensor operative to provide an output signal indicative of the ambient air temperature, a humidity sensor operative to provide an indication of the ambient humidity, a pulsed signal generator connected to said temperature and humidity sensors and operative to generate a pulsed electrical signal the frequency of which is dependent on the ambient temperature and humidity, a plurality of monitor counters, control means responsive to successively generated said infestation signals from said timer means to cause successive ones of said monitor counters to start counting the pulses produced at the output of the said pulsed signal generator, the counts of each counting monitor counter being indicative of the advance of a corresponding infestation detected by the apparatus, and output and display means operable to provide a visual indication of the current counts of said monitor counters.