Plant Health Update, June 2025

Published Jul. 2025|Id: EPP-25-34

By Plant Disease and Insect Diagnostic Laboratory

Each year in May and June, many roses develop symptoms of rose rosette disease (Figure 1). This is a widespread problem in Oklahoma, but the disease is found in many areas of the United States. Fact sheet EPP-7329 Rose Rosette Disease thoroughly describes the symptoms, disease cycle and management of the disease.

A rose bush with normal blooms and leaves on the left side and rose rosette disease on the right side.

Figure 1. The left side of this rose has normal blooms and leaves. The circled area on the right side is disfigured by rose rosette disease.

Although growers attempt to remove rose rosette symptoms by pruning, this is rarely successful. By the time the symptoms are observed, the rose rosette virus has moved throughout the plant. Symptomatic plant parts may be removed by pruning, but it is not surprising when new growth develops, and it has symptoms of the disease. Even if rose rosette is present in your area, roses add beauty to the landscape and are still suggested as short-term perennials.

Each month, a summary of plant health problems from Oklahoma specialty crop growers (horticultural crops) is provided (Table 1). Sample volume has been high following a rainy spring and rapid transition to hot and drier conditions.

Table 1. Summary of samples and diagnostic results for June 2025 from Oklahoma Specialty Crop Growers.

Table 1a. Key for Diagnostic Testing Methods
Key	Diagnostics Method
DD	Digital Diagnosis
M	Microscopy
S	Serological tests
C	Culture analysis
N	Nematode analysis
MD	Molecular diagnostic methods
DS	DNA sequencing
RS	Referral to specialist
O	Other diagnostic tests

Table 1b. Summary of samples and diagnostic results for June 2025 from Oklahoma Specialty Crop Growers.
Number	Host	County	Diagnosis/Identification	DD	M	S	C	N	MD	DS	O
1	American elm	Oklahoma	Canker (Botryosphaeria dothidea)		X		X		X	X
2	Apple	Choctaw	Environmental injury suspected		X	X
3	Apple	Pontotoc	Fire blight, cedar-apple rust	X
4	Apricot	Stephens	Insect damage	X
5	Austrian pine	Cleveland	Pine wilt not found		X			X
6	Austrian pine	Cleveland	Pine wilt not found		X			X
7	Bermudagrass	Kingfisher	Slime mold	X
8	Bermudagrass	Garfield	Winter kill	X
9	Bermudagrass	n/a	Spring dead spot	X
10	Bermudagrass	Oklahoma	Bipolaris and Curvularia leaf spot		X		X		X	X
11	Black-jack oak	Oklahoma	Botryosphaeria canker		X
12	Blue atlas cedar	Payne	Environmental stress	X
13	Blue atlas cedar	Payne	Environmental stress	X
14	Boxwood	Cherokee	Environmental problem		X		X		X	X
15	Boxwood	Cherokee	Colletotrichum leaf spot, anthracnose		x
16	Boxwood	Seminole	Spider mites; Branch dieback	X
17	Cantaloupe	Payne	Alternaria leaf spot		X
18	Cantaloupe	Payne	Rhizoctonia and Pythium root and stem rot		X		X		X	X
19	Cherry	McClain	Branch canker and dieback	X
20	Chinese juniper	Pottawatomie	Environmental stress		X		X		X	X
21	Chokeberry	Cherokee	Bacterial blight (Pseudomonas), Botroysphaeria dothidea		X		X		X	X
22	Crabapple	Oklahoma	Branch canker and dieback		X	X
23	Crabapple	Muskogee	Fire blight		X	X
24	Crape myrtle	Beaver	Aphids suspected	X
25	Crape Myrtle	Seminole	Environmental stress	X
26	Cucumber	Payne	Spider mites suspected	X
27	Cucumber	Osage	No pest or pathogen found		X
28	Dogwood	Payne	Spider mites		X
29	Eastern red cedar	Rogers	Branch canker and dieback	X
30	Eastern redbud	Stephens	Root or wilt problem	X
31	Elm	Harper	Mushroom, Wood borer damage	X
32	Evergreens	Tulsa	Bagworm control recommendation	X
33	Fescue	Tulsa	Brown patch		X		X		X	X
34	Fescue	Canadian	No pathogen found		X		X		X	X
35	Fescue	Tulsa	Brown patch		X		X		X	X
36	Fescue	Canadian	Pythium blight suspected		X		X		X	X
37	Fescue	Canadian	Pythium blight		X		X		X	X
38	Flowering quince	Kiowa	Nutrient deficiency suspected	X
39	Garden	Oklahoma	Fungus gnat		X
40	Grape	Payne	Suspected herbicide injury		X	X			X
41	Grape	Texas	Environmental stresses	X
42	Green been	Rogers	Herbicide injury		X
43	Hackberry	Kiowa	Hackberry nipple gall	X
44	Holly	Beckham	Spin spot; Phoma leaf spot		X		X		X	X
45	Holly	Oklahoma	Botryosphaeria canker		X		X		X	X
46	Holly	Kiowa	Spine spot, herbicide injury suspected	X
47	Hydrangea	Rogers	Cercospora leaf spot	X
48	Juniper	Tulsa	Transplant shock, injury		X						X
49	Lacebark elm	Cleveland	Excessive water	X
50	Lilac	Logan	Insufficient sample	X
51	Magnolia	Garfield	Lichens	X
52	Maple	Oklahoma	Botryosphaeria canker; Sunscald		X		X		X	X
53	Maple	Wagoner	Sapsucker damage	X
54	Maple	Logan	Iron chorosis	X
55	Mesquite	Jackson	Undetermined injury		X
56	Mexicana squash	Payne	Rhizoctonia root and stem rot		X		X		X	X
57	Mugo pine	Oklahoma	Diplodia tip blight, Dothistroma needle blight		X
58	Mugo pine	Oklahoma	Dothistroma needle blight		X
59	Mulberry	Beckham	Herbicide injury suspected	X
60	Mulberry	Garfield	Environmental stress	X
61	Mulberry	Oklahoma	Bacterial wetwood	X
62	Oak	Oklahoma	Oak anthracnose	X
63	Oak	Oklahoma	Environmental stress, insect damage	X
64	Oak	Kingfisher	Iron chlorosis	X
65	Oak	Wagoner	Lightning damage suspected	X
66	Oak	Okfuskee	Insect damage suspected	X
67	Oak	Oklahoma	Environmental stress		X		X
68	Oak	Oklahoma	Jumping oak gall suspected	X
69	Oak	Oklahoma	Oak anthracnose	X
70	Oak	McClain	Iron chlorosis	X
71	Oak	Oklahoma	Iron chlorosis, branch canker	X
72	Oak	Kiowa	Oak anthracnose, Iron chlorosis	X
73	Oak	Wagoner	Lightning injury suspected	X
74	Oak	Grady	Scales, Wood borer	X
75	Oak	Logan	Iron chorosis	X
76	Peach	Garfield	Bacterial leaf spot, hail damage		X	X
77	Pear	Beckham	Iron chorosis		X	X
78	Pear	Alfalfa	Pear rust, Wood borer damage, herbicide injury	X
79	Pear	Nowata	Fire blight and Black rot	X
80	Pecan	Lincoln	Pecan stem phylloxera		X
81	Pecan	Payne	Pecan scab		X		X		X	X
82	Pecan	Payne	Pecan scab		X		X		X	X
83	Pecan	Payne	Pecan scab		X		X		X	X
84	Pecan	Payne	Herbicide injury		X
85	Pecan	Stephens	Environmental stresses	X
86	Pecan	Kiowa	Black pecan aphid suspected	X
87	Peony	Muskogee	Bacterial leaf spot-Xanthomonas		X	X
88	Pepper	Osage	No pest or pathogen found		X
89	Pine	Stephens	Environmental stress	X
90	Pine	Texas	Environmental stress	X
91	Pine	Payne	Dothistroma needle blight		X
92	Pine	Payne	pH induced pathology, Dothistroma		X
93	Pine	Texas	Nantucket pine tip moth suspected	X
94	Pine	Washita	Woodpecker damage	X
95	Pine	Texas	Transplant shock or root problem	X
96	Plant ID request	Seminole	Oak, white oak group	X
97	Plant ID request	Seminole	Ash	X
98	Post oak	Oklahoma	Botryosphaeria dieback		X
99	Pricklypear	n/a	Cactus bugs, Cochineal scales	X	X
100	Privet	Payne	Phomopsis canker, Pythium root rot		X		X		X	X
101	Redbud	Garfield	Fungal leaf spot	X
102	Redbud	Pottawatomie	No pathogen found, Edema suspected		X		X		X	X
103	Redbud	Pontotoc	Herbicide injury suspected	X
104	Redbud	Pottawatomie	No pathogen found, Edema suspected		X		X		X	X
105	River birch	Okfuskee	Nutritional deficiency suspected	X
106	Rocky mountain juniper	Oklahoma	Canker (Diplodia cupressi and Seridium sp.)		X		X		X	X
107	Rose	Rogers	Botrytis blight	X
108	Rose	Oklahoma	Rose rosette	X
109	Rose	Oklahoma	Rose rosette	X
110	Rose	Washita	Flower balling	X
111	Rose	Garfield	Environmental stress	X
112	Rose	Kiowa	Rose mosaic virus	X
113	Rose of Sharon	Garfield	Environmental stress	X
114	Shumard oak	Oklahoma	Oak anthracnose		X
115	Spaghetti squash	Payne	Fusarium stem and crown rot		X		X		X	X
116	Spruce	Texas	Mechanical damage	X
117	Squash	Payne	Plectosphaerella blight, Fusarium root/crown rot		X		X		X	X
118	Squash	Pontotoc	Leaf spot (unidentified cause)	X
119	St. Augustinegrass	Marshall	Take all disease		X			X
120	Sweet Gum	Cherokee	Phomopsis/Diaporthe leaf spot		X		X		X	X
121	Sweet gum	Stephens	Environmental/cultural problem	X
122	Tomato	Oklahoma	Herbicide injury		X	X			X
123	Tomato	McIntosh	Mites, nutritional deficiency	X
124	Tomato	Rogers	Environmental problem	X
125	Tomato	Payne	Physiological leaf roll	X
126	Tomato	Choctaw	Bacterial wilt, Phytophthora root rot		X	X
127	Tomato	Pottawatomie	Herbicide injury suspected		X	X
128	Tomato	Garfield	Herbicide injury suspected	X
129	Tomato	Alfalfa	Herbicide injury suspected	X
130	Tomato	Payne	Fusarium root and stem rot		X		X		X	X
131	Tomato	Payne	Bacterial canker		X	X
132	Tomato	Pottawatomie	Herbicide injury suspected		X	X			X
133	Tomato	Rogers	Herbicide injury suspected		X
134	Tree	Oklahoma	Brumelia borer suspected	X
135	Turfgrass	Garfield	Compaction	X
136	Vegetables	Payne	Assassin bug	X
137	Woody ornamental	Okfuskee	Herbicide injury suspected	X
138	Yellow squash	Payne	Mucor rot		X		X
139	Zelkova	Texas	Insect damage suspected	X
140	Zinnia	Kay	No virus found; herbicide injury suspected		X	X			X
141	Zucchini	Payne	Fusarium root/crown rot, Plectosphaerella blight		X		X		X	X

The number of samples from oak trees submitted has been notably high. Many trees have symptoms of anthracnose (Figure 2). This disease causes distortion, discoloration, and tip dieback of oak trees. At this time of the year, pruning to removed diseased shoots is suggested. If the disease caused significant damage to an oak tree, consider contacting an arborist about fungicide injections. The fungus overwinters in the twigs and next spring, additional leaves may become infected if the disease was not “pruned out”. Fungicides can be applied next spring, at budbreak, to prevent new infections.

The leaves on an oak tree are showing distortion and disfiguration from being affected by oak anthracnose.

Figure 2. Oak leaves with distortion and disfiguration due to oak anthracnose. Image provided by Arborscapes Tree Services, Inc.

Each summer, the PDIDL receives inquiries about oak trees that are in decline, and clients inquire if oak wilt disease is the cause. The PDIDL has been in existence for +40 years and we do not have any confirmations of oak wilt caused by Bretziella fagacearum in our records. Oak trees most often show decline because of environmental stress factors (temperature extremes, drought , storm damage). Most of the more serious problems that develop on oak trees occur when trees are predisposed by other problems. It is vital to provide supplemental irrigation during periods of heat and drought, especially to oak trees in urban areas. When trees suffer damage from hail, wind, or ice, remove injured limbs by pruning as early as possible. Many fungi that affect oak trees are opportunistic. They will enter the tree through the injury site(s).

If you are concerned about an oak tree or other landscape plants, it is helpful to start by taking images. These can be submitted to your local county extension office and if needed, forwarded by the extension educator to the PDIDL. Images should be taken at a large size (high resolution). Start by taking images of the whole plant from a few different angles. Then, take closer images, zooming in on problem areas. After the images are reviewed, it will be determined if a physical specimen is needed.

Look for additional plant health updates from the PDIDL throughout 2025. If you have suggestions for future topics, please contact jen.olson@okstate.edu or call the PDIDL at (405) 744-9961.

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Plant Health Update, June 2025