TABLE 1.

Disease severity of Ulmus americana saplings inoculated with Ophiostoma novo-ulmi H327 wild-type, NHEJ-defective mutant strain 174_68Δmus52, and two adenine auxotrophs (ade1-6 and ade7-13) derived from it by targeted deletion of genes ade1 and ade7.

	Disease severity
		95% Confidence interval
Treatment	Percent*	Lower limit	Upper limit
Water	10.3 a	7.8	12.8
O. novo-ulmi H327 (WT)	99.0 b	96.5	100.0
174_68Δmus 52 (Δmus52)	99.7 b	97.2	100.0
ade1-6 (Δmus52Δade1)	4.0 a	1.0	7.0
ade7-13 (Δmus52Δade7)	3.0 a	0.2	6,2

*Median of percent disease severity (defoliation) at 21 days post inoculation. Different letters indicate statistically significant differences (P < 0.05) according to a Bonferroni test.