Stripe Rust Update, May 21, 2025

Stripe rust has been developing in Washington

Since the last stripe rust update on May 7, stripe rust has been developing in the Pacific Northwest (PNW), especially in Washington. After the update, we received a report of stripe rust in commercial fields of winter wheat in Franklin County, Washington. On May 9, we checked the fields planted with Piranha CL+ and Nova AX, and stripe rust was easy to find (Figure 1) although the incidence was less than 1%. The Nova AX field was sprayed with fungicides a day before and the Piranha field was sprayed on that day. We checked more than ten additional commercial fields of winter wheat fields in Franklin and Adams counties and found stripe rust in three fields with incidence less than 0.1%.

Figure 1: Stripe rust in a commercial field planted with winter wheat variety Piranha CL+ in Franklin County, Washington on May 9, 2025.

On May 15, we were checking our experimental fields around Pullman, Washington (Whitman County). Stripe rust was easier to find than a week earlier on spreader rows planted with a highly susceptible winter wheat variety, but still below 1% incidence. No rust was found in commercial winter wheat fields in the Palouse region.

On May 20, we were taking stripe rust data in our winter germplasm screening nurseries at the Central Ferry station (Garfield County), Washington. Winter wheat reached the flowering stage (Feekes 10.51-10.53) and barley reached Feekes 10.53-10.54. As expected, stripe rust reached 90 to 100% severity on susceptible varieties of both wheat and barley (Figure 2). The stripe rust fungus turned into the black telial stage (Figure 3), which no longer produces infectious, orange-colored spores. Some strains of the stripe rust fungus turn into the telial stage faster than others.

Figure 2: Stripe rust in an experimental field in Central Ferry (Garfield County), Washington on May 20, 2025.

Figure 2: Stripe rust black telial pustules on a susceptible winter wheat variety in an experimental field in Central Ferry (Garfield County), Washington on May 20, 2025

Stripe rust in the country

Since the last update (May 7), stripe rust has not been reported in any additional states. Thus, only eight states, Louisiana, Texas, Georgia, Washington, Oregon, California, Oklahoma, and Kansas, have been reported to have stripe rust so far. Even in these states, stripe rust has appeared at relatively low levels compared to last year, except California. However, stripe rust may still have time and conditions to develop to epidemic levels in some regions.

Sequence of Class	VT Name	2025 PLOT	Mount Vernon		Central Ferry		Sequence of Class	VT Name	2025 PLOT	Mount Vernon		Central Ferry
			4/15/2025		5/20/2025					4/15/2025		5/20/2025
			Feekes 5		Feekes 10.54					Feekes 5		Feekes 10.54
			IT*	%	IT*	%				IT*	%	IT*	%
1	AAC Vortex	1	2	20	3	5	26	LWW22-6372	64	2	20	2	2
2	Bridger	2	2	20	2	5	27	LWW22-6387	65	5	40	2	2
3	CO19D087R	3	2	15	3	5	28	LWWA22-S22 AX	66	2	20	2	2
4	CP7909	4	2	20	8	20	29	Nimbus	67	2	10	2	2
5	CS Bridger CLP	5	3	30	2	5	30	Norwest Tandem	68	2	20	2	2
6	GHR22-3	6	3	30	2	2	31	OR2170559	69	2	10	3	5
7	GSHR5	7	3	30	2	2	32	OR2180149	70	2	20	3	20
8	HSG 086	8	2	20	3	5	33	OR2180350	71	2	20	3	10
9	HSG 124	9	3	30	2	2	34	OR2190671	72	2	30	2	5
10	Irv	10	2	20	2	2	35	OR2200130	73	2	20	2	2
11	Kairos	11	2	10	2	2	36	OR5180071	74	2	10	2	10
12	Kivari AX	12	5	50	8	10	37	OR5180072	75	2	20	2	5
13	LCS Blackbird	13	2	10	2	2	38	OR5190014	76	2	20	2	10
14	LCS Eclipse AX	14	2	10	2	2	39	OR5210096	77	2	20	2	2
15	LCS Missile	15	2	10	2	2	40	PN18MS604566	78	5	60	3	20
16	LWH20-0490	16	3	30	2	2	41	Rosalyn	79	5	40	2	2
17	LWH21-0760	17	2	20	2	2	42	TMC M-Pire	80	2	30	2	2
18	LWH21-5237	18	2	15	2	2	CHK	PS279 (S. check)	81	9	70	9	100
19	LWH22-0087	19	2	20	2,8	2,10	43	TMC M-Press	82	2	20	2	2
20	LWH22-1003	20	2	15	2	2	44	VI Gem	83	2	20	2	2
CHK	PS279 (S. check)	21	9	70	9	95	45	WA8426	84	2	10	2	2
21	LWH22-5463	22	2	10	2	2	46	WA8438	85	2	20	3	5
22	Millie	23	2	10	2	2	47	WA8439	86	2	15	2	2
23	OR2190064R	24	2	20	2	5	48	WA8441	87	2	20	2	2
24	OR2190160R	25	2	15	2	2	49	WA8442	88	2	10	2	10
25	OR2190165R	26	2	10	2	2	50	WA8447	89	5	30	3	10
26	OR3230008H	27	2	10	2	2	51	WA8448	90	3	30	2,8	2,80
27	OR3230010H AX	28	2	10	8	5	52	WA8451 MZ	91	2	30	3	20
28	OR3230015H AX	29	2	10	2	2	53	WB1621	92	2	10	3	15
29	WA8368	30	2	20	8	10	54	WB1720	93	3	30	2	2
30	WA8424	31	2	15	2	2	55	WB1922	94	3	40	2	5
31	WA8425	32	2	10	2	2	56	XH1046	95	2	10	8	30
32	WA8449	33	2	20	2	2	57	WFX69113	96	5	60	5	50
33	WB4303	34	2	20	8	30	58	WFX69333	97	2	30	3	15
34	WB4510CLP	35	2	20	2	2	59	XG1305	98	2	10	7	30
35	WB4640	36	2	30	5	30	1	Appleby CL+	99	2	20	2	15
1	14-211120A	37	2	15	2	2	2	Curiosity CL+	100	3	30	5	40
2	16-007057A	38	2	20	2	2	CHK	PS279 (S. check)	101	9	70	9	100
3	16-478001	39	2	15	2	2	3	LCS Dagger AX	102	3	30	8	70
4	17-355144A	40	2	20	2	2	4	LCS Hydra AX	103	2	10	2	10
CHK	PS279 (S. check)	41	9	70	9	95	5	LCS Reaper II AX	104	3	20	2,8	2,80
5	17-995133B	42	2	20	2	2	6	LCS Scorpion AX	105	2	20	2	2
6	AP Iliad	43	2	15	2	2	7	LWHA21-5188 AX	106	2	20	3	15
7	AP Olympia	44	2	10	2	2	8	LWHA22-0008 AX	107	2	20	3	15
8	ARS Crescent	45	3	20	2	2	9	LWWA22-H22 AX	108	2	20	3	30
9	Bobtail	46	5	50	5	20	10	LWWA22-S22 AX	109	2	15	2	2
10	Gale (OR2180377)	47	2	20	2	2	11	LWWC21-0317 CL+	110	2	10	3	20
11	GS Bounty	48	2	20	5	10	12	LWWC21-5070 CL+	111	2	30	5	40
12	GSW22-21	49	2	20	7	30	13	Mallory CL+	112	2	20	2	2
13	LCS Artdeco	50	3	30	3	10	14	OR2200083 CL+	113	2	30	2	2
14	LCS Blackjack	51	2	20	2	2	15	OR3230013 AX	114	2	20	2	5
15	LWW20-2383	52	2	10	2	2	16	OR3230026 AX	115	2	20	2	2
16	LWW20-2867	53	2	10	2	2	17	Resilience CL+	116	2	10	2	2
17	LWW20-3371	54	2	15	2	2	18	UIL 19-713070A CL+	117	2	20	2	2
18	LWW21-1436	55	2	20	2	2	19	VI Encore CL+	118	2	20	2	2
19	LWW21-1554	56	2	10	2	2	20	VI Presto CL+	119	2	20	2,8	2,20
20	LWW22-0837	57	2	30	2	2	21	WA8443 AX	120	5	40	3	10
21	LWW22-1105	58	2	20	2	2	CHK	PS279 (S.check)	121	9	70	9	95
22	LWW22-1232	59	3	30	2	2	22	WA8444 AX	122	2	10	8	20
23	LWW22-2425	60	3	30	2	2	23	WA8445 CL+	123	2	15	2	2
CHK	PS279 (S. check)	61	9	70	9	95	24	WA8446 CL+	124	2	15	2	2
24	LWW22-2864	62	3	30	2	2	CHK	PS279 (S. check)	125	9	70	9	95
25	LWW22-4020	63	2	10	2	2	CHK	PS279 (S. check)	126	9	70	9	95
* IT = infection type.  ITs 0-3 are considered resistant (R), 4-5 moderately resistant (MR), 6-7 moderately susceptible (MS), and 8-9 susceptible.