Issue 4, June 1, 2020
Summary of ornamental, fruit, and vegetable samples
It’s no surprise that our sample numbers are lower than usual this year. While the Plant Clinic remains open, we are currently operating with staff in the lab only as needed for diagnostics. We are often not able to answer or return phone calls in a timely manner. If you need to contact us, we suggest emailing plantclinic@illinois.edu for the fastest response.
Packages shipped via USPS are being picked up 3-4 times a week. FedEx packages are picked up as packages arrive, and UPS is delivering packages daily. No matter how you send a sample, we highly recommend keeping your tracking number and checking to see if the sample was delivered. If you notice that the package wasn’t able to be delivered (a delivery attempt or delivery failure), please contact us with the tracking number and the method used to ship the sample – we may be able to track it down locally.
Boxwood samples were by far the most common over the last two months, accounting for almost 29% of samples received. While we have not diagnosed boxwood blight yet this year, it’s still a concern, especially in the northern part of the state. For more information about boxwood blight, please see: http://hyg.ipm.illinois.edu/article.php?id=869 and http://hyg.ipm.illinois.edu/article.php?id=1137.
We’re seeing a lot of needle blights and needle casts on fir, spruce, and arborvitae; this is not uncommon in spring. Many of these diseases attack stressed plants, so reducing stress by selecting the correct plant for the location, planting to the proper depth, pruning during dry weather, fertilizing appropriately, watering during periods of dryness, and mulching will all help reduce the severity of these diseases.
Host |
Pathogens and/or Pests Confirmed (C) or Suspected (S) |
Arborvitae |
Phyllosticta needle blight (C) |
Fir |
Phyllosticta needle blight (C), Rhizosphaera needle cast (C), environmental stress (S) |
Spruce, Colorado Blue |
Rhizosphaera needle cast (C), Stigmina needle blight (C), environmental stress (S), Sudden Needle Drop (C), Spruce Spidermite (S) |
Spruce |
Rhizosphaera needle cast (C), Spruce spidermite (S), environmental or chemical damage (S) |
Eastern White Pine |
Environmental stress (S), White Pine Decline (S) |
Ash |
Thrips (C) |
Japanese Maple |
Environmental stress (S) |
Pin Oak |
Gnarled Oak Leaf Midge Gall (C) |
River Birch |
Environmental stress (S) |
Serviceberry |
Entomosporium leaf spot (C), Leafhopper (S) |
Rose |
Fungal canker (C) |
Boxwood |
Volutella blight (C), Fusarium canker (C), Macrophoma leaf spot (C), Boxwood leafminer (C), Boxwood psyllid (C), Boxwood spidermite (S), environmental stress (S) |
Pachysandra |
Volutella blight (C), Edema (C) |
Sedum |
Edema (C) |
Penstemon |
Impatiens Necrotic Leaf Spot Virus (C) |
Basil |
Bacterial stem necrosis (C), Fusarium wilt (C) |
Lettuce |
Pythium root rot (C) |
Strawberry |
Aphids (C) |
Author:
Diane Plewa