No. 10/August 30, 2019

Magnolia Scale
Magnolia scale (Neolecanium carnuparvum) is a pest of magnolia, including star, cucumbertree, saucer and lily magnolias in northern and central Illinois. This insect can produce a large amount of honeydew, making leaves and branches shiny and sticky. The honeydew can promote sooty mold growth on the affected area, turning leaves and branches dark gray or black. If large populations of scales are present, honeydew can also coat lawn furniture or cars below the magnolia tree causing additional nuisance.

Oak lace bug
It was stippling on the oak leaves (a visible insect feeding pattern) that caused me to stop and take a closer look. I thought it might be spider mites. Frass (insect excrement) in the form of black droplets on the underside of the leaf told me this was a phloem feeder. Then the culprits moved when I poked at them. They were oak lace bugs (Corythucha arcuata). Oak lace bugs are about 1/4 inch long with clear to white wings that are flat rectangular-shaped with dark brown markings that give the appearance a miniature cut square of lace.

Mulberry Tree Seedlings in the Lawn and Landscape
My relationship with mulberry is bittersweet. I have fond memories of picking the berry-like fruits as a child and using them to decorate the mud pies we had made. My own children love picking and eating the fruits as well. However, as an adult, my love of mulberry has soured a bit and my children are sad when I express my strong disdain for it. The fact is that white mulberry (Morus alba) is a weedy species and as a gardener with mulberry trees in the neighborhood, I have removed hundreds if not thousands of young mulberry seedlings from my property over the last 20 years. Perhaps my children should assist with those efforts in order to gain a new understanding of the downsides to having mulberry trees nearby.

Bur Oak Blight
The U of I Plant Clinic has received several tree samples suspected to be infected with bur oak blight (BOB). So far, for 2019, the plant clinic has confirmed BOB on two samples, originating in Cook and Henry counties. While still considered a relatively newly pathogen, we have seen an increase in awareness of this disease compared to just a few years ago.

Phosphorus Law Reminder for Illinois Turf Managers
Are you an applicator for hire who applies fertilizer to lawns? Does the fertilizer you use contain phosphorus? What is the big deal about phosphorous? Phosphorous (P) is a critical macro nutrient required for plant growth. It aids in processes like photosynthesis, it plays a role with diseases incidences, and it is also involved in the reproduction process. With adequate phosphorous spring green up is better. Without P turf grass plants are spindly and dwarfed, and often they will have a purple discoloration along the leaf blade as the deficiency progresses. It is second to nitrogen as an essential plant nutrient that ensures plant function and health. These functions enable the lawn/turf to be healthy and dense. Knowing that P is important, we must also be aware of legislation that can affect your ability to apply P to lawns. In 2010, Illinois Legislature passed a bill that restricts any applicator for hire from applying phosphorus-containing fertilizers to a lawn unless a recently conducted soil test indicates a phosphorus deficiency. Notably, homeowners are exempt from this requirement. Areas that are exempt include commercial farms, lands classified as agricultural lands, and golf courses. Product exemptions are discussed below. An Illinois Department of Agriculture Inspector noted that they have found applicators that were in violation of applying phosphorous. Violators can find themselves charged with a penalty of $250 for the first violation. Penalties increase to $500 and $1,000 for second and subsequent violations, respectively.