Sensitivity of Bud Rot (Phytophthora sp.) Isolated from Coconut Palms in Jamaica to local Commercial Fungicide Pilarzox and Turmeric powder

Bud rot, caused by Phytophthora sp., poses a significant threat to coconut palm production in tropical regions. This study evaluated the in vitro efficacy of the commercial fungicide Pilarzox (containing the active ingredients Cyazofamid and Cymoxanil) and turmeric (Curcuma longa) extract against Phytophthora isolates obtained from symptomatic coconut palms in St. Mary, Jamaica. Using the poisoned agar technique, three independent Phytophthora isolates were tested in five technical replicates across ten concentrations (0, 100, 150, 200, 250, 300, 500, 1,000, 5,000, and 10,000 ppm). Diagnostic tests confirmed homogeneity of variance, validating the use of ANOVA and Tukey’s HSD for statistical comparisons. Results indicated that Cyazofamid achieved complete inhibition at 500 ppm, whereas Cymoxanil required concentrations between 1,000 and 5,000 ppm for full inhibition. In contrast, turmeric exhibited a maximum inhibition of only 12% at 10,000 ppm. These findings suggest that local Phytophthora populations may have developed resistance to conventional fungicides, and while turmeric shows limited efficacy as a stand-alone agent, it may be useful as part of an integrated management strategy. Further field trials and mechanistic studies are recommended.

(Batuman et al., 2020; Ivanov et al., 2021; Murugesh et al., 2019; Jones et al., 2023)