Can spore trapping be of help in black currant mildew control?

In the UK growers control black currant mildew, caused by Sphaerotheca mors -uvae, by routine spray programmes starting in early to mid-May. A study wa s undertaken to monitor ascospore release from overwintering cleistocarps a nd to relate this to the first sign of leaf infection. Sticky rod spore tra ps were monitored from mid-March to mid-May, but ascospore release had star ted even earlier in the season and continued until late May. At the two sit es monitored leaf infection did not occur until temperatures reached 18 deg rees C, despite peak of spore catches when temperatures were lower. It appe ared that spore trapping would not be useful in helping growers decide when to start their preventative fungicide programme.