No. 5/June 17, 2021

Modified Growing Degree Days (Base 50⁰ F, March 1 through June 13)
Insect development is temperature dependent. We can use degree days to help predict insect emergence and activity. Home, Yard, and Garden readers can use the links below with the degree day accumulations above to determine what insect pests could be active in their area.

May 2021 Plant Clinic Sample Summary
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; MWF are the best days to contact us due to staffing schedules. You can also email us at

Aphids (Family: Aphidae) are one of the most common insect pests in the home landscape. They have small, pear-shaped bodies that can be many colors, including green, brown and yellow. Aphids can be identified by small structures called cornicles, which look like tailpipes on the rear ends of the insects. Aphids can be winged or wingless, with winged individuals appearing later in the season. Aphids can have many generations in a single year, so it is a good insect to scout for throughout the growing season.

Black Knot
Purple-leaved plants are a great way to add color to a landscape. For plants like purple common smoketree, purple European beech, and prairifire crabapple, the purple color is most intense on the newly emerged leaves before changing to a purple-green or dark green for the summer. Schubert chokecherry does the opposite, with leaves that emerge green and turn to a rich reddish-purple for the remainder of the season. As attractive as that sounds, this plant is a fairly short-lived species that is highly susceptible to black knot.

Oak Leaf Blister
I have lived in my current home for several years. Every year, except for one abnormally dry spring, I’ve watched oak leaf blister infection develop on my black oak. I often use my tree as an example of how weather can influence disease pressure. 

Understanding and Preventing Off-target Movement of Herbicides
Off-target movement occurs when a pesticide moves out of the area intended for application and can cause damage to desirable vegetation, humans, and wildlife. Any pesticide can move off-target but herbicides tend to result in the most easily visible damage. In this article, we will discuss the different types off-target movement, the factors that influence each, prevention, and why this topic is more important now than ever before. When applicators are more informed and have a better understanding of these issues, they can act accordingly to better keep their applications on target.

EPA Webinar: Pesticide Labels Demystified- Pesticide Label Guidance
The Environmental Protection Agency (EPA) Center for Integrated Pest Management (IPM) is hosting a webinar called – Pesticide Labels Demystified: Guidance on how to Read Pesticide Labels. . A key component of integrated pest management (IPM) is the appropriate and safe use of pesticides. Understanding how to read, interpret, and follow instructions on a pesticide label is critical to the safe use of the product. EPA hosts this free webinar to gain a better understanding of the intent of the guidance provided on these labels, which is critical to the safe use of the product. It will be held live on June 22, 2021 from 2:00 to 3:30 pm ET.