Y18501, an oxysterol-binding protein (OSBPI) inhibitor structurally akin to Oxathiapiprolin, demonstrates potent inhibition against Phytophthora spp. and Pseudoperonospora cubensis with EC50 values between 0.0005 and 0.0046 μg/mL. It exhibits exceptional protective and curative effects on P. cubensis. When used in tandem with Chlorothalonil, Y18501 markedly enhances the suppression of P. cubensis [1].

Y18501, at application rates of either 25 g a.i./ha or 50 g a.i./ha, demonstrated control efficacy exceeding 60% against cucumber downy mildew under greenhouse conditions [1]. In both greenhouse and field settings, Y18501 exhibited control efficacies of 72.3% and 78.9% at 25 g a.i./ha, and 80.8% and 82.2% at 50 g a.i./ha, respectively [1]. The protective activity of Y1850 (10.012-0.333 μg/mL) was greater than its curative activity; treatment with Y1850 24 hours prior to inoculation resulted in control efficacies of 70.11 and 99.43%, significantly higher than treatments administered 24 hours post-inoculation [1]. Synergistic effects against cucumber downy mildew were noted when Y18501 was combined with Chlorothalonil at ratios of 1:100, 1:70, and 1:50, with synergy ratios of 2.00, 1.83, and 2.64, respectively [1].