TABLE 1.

Significant correlations (p < 0.05) with a Pearson’s value over ±0.5 between feature intensity and conidia count across cultivars and treatments (n = 9).

Feature ID	Putative ID	Pearson correlation	Sig. (two-tailed)
9	Chlorogenic acid	−0.51	*
11	Unidentified	−0.62	*
17	Quercetin-3-glucuronide	−0.52	*
19	Quercetin 3-O (6-malonyl)-glucoside	−0.68	**
20	3,5-Dicaffeoylquinic acid	−0.61	*
22	Unidentified	−0.55	*
24	Unidentified	−0.56	*
27	Unidentified	−0.53	*
29	Unidentified	−0.52	*
33	Nitrogen containing lipid	0.55	*

Lettuce (L. sativa) cultivars (El Dorado, Iceberg, and Salinas) were treated with photosynthetically active radiation (PAR)+UV-B or PAR only (control) for 3 days. Following treatment, samples were taken for liquid chromatography–mass spectrometry (LC-MS), with the remaining plants inoculated with 10⁵ conidia mL^–1 of B. lactucae. Plants were harvested for conidia count at 12 days post-inoculation. A bivariate correlation analysis was carried out on all LC-MS features and disease symptoms. Information on feature IDs is provided in Supplementary Table 1. Significance level is indicated by asterisks where *p < 0.05, **p < 0.005.