Issue 9, August 12, 2021

July 2021 Plant Clinic Sample Summary

Summary of ornamental, fruit, and vegetable samples diagnosed July 2021.

The Plant Clinic remains open. We are currently operating with reduced staff and are only in the lab as needed for diagnostics and other lab work. We may not be able to answer or return phone calls in a timely manner though we are making every attempt to do so. You can also email us at

Samples shipped via USPS, UPS, and FedEx are all arriving in a timely manner. We recommend shipping early in the week (Monday-Wednesday) and keeping the tracking number so we can trace the package if needed.

We are receiving more maple and oak samples. Another red oak sample from Lake Co. tested positive for Oak Wilt (, a lethal oak disease. As a reminder, do not prune oak trees during the growing season!

Another sample of boxwood from Cook Co. was confirmed with Boxwood blight. For more information, please see: and

Dogwood anthracnose was confirmed on a sample from Sangamon Co.

Southern blight was confirmed on coneflower from Champaign Coounty. Southern blight was confirmed on coneflower from Champaign Co. Please view the Southern Blight artile within this issue of the Home, Yard, and Garden Pest Newsletter for more information about this disease.

We’re also starting to see environmental scorch symptoms and symptoms characteristic of bacterial leaf scorch. We will be testing for bacterial leaf scorch later in the year (September and October). Samples can be submitted now and will be stored until we begin tests. For more information about bacterial leaf scorch, please see:

We’re also seeing a lot of white oak samples with kermes scale, everything from mild to severe infestations ( The number of samples with twospotted spider mites ( is also increasing which is not surprising as we get into hot, dry weather.

Host Pathogens and/or Pests Confirmed (C) or Suspected (S)
Apple Bully’s eye rot (C)
Arborvitae Phomopsis needle blight (C), Phyllosticta needle blight (C), Pestalotiopsis needle blight (C)
Blackeyed Susan Downy mildew (C), Septoria leaf spot (C)
Boxwood Boxwood blight (C), Volutella blight (C), Fusarium canker (C), Boxwood leafminer (C), Boxwood spidermite (S), Boxwood psyllid (C), Macrophoma leaf spot (C)
Catalpa Phyllosticta leaf spot (C)
Coneflower Southern blight (C)
Cucumber Anthracnose (C), Fusarium wilt (C)
Dogwood Dogwood anthracnose (C), Fungal cankers (C)
Fir Phyllosticta needle blight (C), environmental stress (S)
Horsechestnut Guignardia leaf blotch (C)
Hydrangea Bacterial blight (C), Twospotted spider mite (C)
Lavender Phytophthora root rot (C)
Lilac Leaf spot (C)
Magnolia Fungal cankers (C), sooty mold (C)
Maple Anthracnose (C), Aphids (C), Oystershell scale (C), Gouty vein gall midge (C), Fungal cankers (C), Environmental stress (S)
Oak Oak wilt (C), Kermes scale (C), Jumping oak gall (C), Oak twig canker (C), Oak bullet gall wasp (C), Fugal cankers (C), Anthracnose (C), Environmental stress (S)
Pear Bacterial Blast (C)
Pepper Bacterial leaf spot (C), Rhizoctonia root rot (C)
Pine Environmental stress (S)
Privet Thrips (C), Environmental stress (S)
Rose Phomopsis canker (C), Rose rosette disease (S), Environmental stress (S)
Spruce Sudden Needle Drop (SNEED) (C), Transplant shock (S), Environmental stress (S)
Sweetgum Anthracnose (C), Environmental stress (S)
Tomato Fusarium wilt (C)
Turf Anthracnose (C), Magnaporthe summer patch (C), Rhizoctonia root rot (C)

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