June 14 University of Illinois Home, Yard, and Garden Newsletter

Hawthorn and Apple Mealybug
Hawthorn mealybug is being found in high numbers on cotoneaster in northeastern Illinois. Hawthorn mealybug, Phenacoccus dearnessi, is also known as two-circuli mealybug. It feeds on hawthorn, cotoneaster, pyracantha, mountain ash, amelanchier, and other rose family plants.

Red Mites
Little red mites are common this year in mulch and damp soil. These mites are bright red with long, obvious red legs. Landscaping crews are probably seeing them and being asked about them by clientele. As the weather warms and the mulch dries, they are moving into buildings. They are a nuisance indoors by their presence, but do not bite humans.

Callery Pear Blights
A year ago, many Callery Pears were showing unsightly symptoms associated with bacterial blast, a disease which caused blighted leaves and shoots throughout the affected tree’s canopy. Pictures and more details on the symptoms of this disease can be found in last years newsletter http://hyg.ipm.illinois.edu/article.php?id=362.

Holly Decline: Fully Utilizing U of I Extension Resources and the Plant Clinic
As a plant diagnostician, I have quickly learned that there are several different types of homeowner mindsets when it comes to diagnosing and managing their landscape problems. There are some plant problems that can be diagnosed over the phone or via a picture and the U of I Plant Clinic is not needed. However, there are complicated plant issues that do not have an easy diagnosis.

Invasive Species Spotlight: Hemlock Woolly Adelgid
The hemlock woolly adelgid was first identified in 1924 in the Pacific Northwest and in the 1950’s in Richmond, Virginia. Infested areas of eastern and Carolina hemlocks in the eastern United States are increasing in number). To date, this invasive insect has not been found in Illinois. It was discovered in Indiana in 2012.

Modified Growing Degree Days (Base 50° F, March 1 through June 14)
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.