We aim to compare the current recommended WA fungicide spray strategy with the more regular fungicide applications common in other states, and with a spray timing based on canopy humidity and temperature to determine if this could be a useful decision support tool by West Australian growers.

DPIRD’s current recommendations of the first spray at flowering and a follow up spray produced similar yields to regular spray treatment which had four fungicide applications. The SARDI alert system was set to Red Alert if temperate was above 15°C and 70% humidity for 12 consecutive hours - which appeared to put too much emphasis on temperature. Whereas if we had used humidity alone the alerts may have occurred much earlier in the year in early August and most likely closely tracked the ‘regular spray’ treatment.