No. 3/May 9, 2016
First Weekly Issue
Starting with this issue and continuing through June, the Home, Yard, and Garden Pest Newsletter will be published weekly. At this time of year, diseases, weeds, and insect pests appear often and in large numbers, making timely control necessary. We will revert to an every two week publishing schedule in July through September when timing is less critical.
Phenology Timing and Bridal Wreath Spirea
Bridal wreath spirea, or Vanhoutte spirea (Spiraea x vanhouttei), is blooming throughout the state. This is a major phenology plant in Don Orton's book Coincide. With phenology, stages of plant development (usually bloom time) are used to predict stages in pest development.
Emerald Ash Borer Control
As reported in Kelly Estes' article in this newsletter issue, emerald ash borer adults are emerging in southern Illinois and will soon do so in central and northern Illinois. Now is the time to apply systemic insecticides to control this pest if emerald ash borer has been found within 15 miles.
Hold Off Pruning Oaks and Elms
Warm spring weather provides ideal working conditions for many landscape maintenance projects. However, some projects, such as pruning, can be harmful if done at the wrong time of year. For example, Oak Wilt and Dutch Elm Disease (DED) are two devastating fungal diseases that are more likely to occur on trees pruned early in the growing season. Recently pruned trees can attract insect vectors that transmit the spores of the fungal pathogens.
Modified Growing Degree Days (Base 50°F, March 1 through April 21)
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.
Emerald Ash Borer Adult Emergence Beginning
We generally think of Memorial Day as the time of year to begin thinking about emerald ash borer emergence. Given the warm weather this spring, the southern part of Illinois has already reached the accumulated degree days to signal adult emergence. This was confirmed last week with adult emergence confirmed in Marion.
2016 Invasive Species Awareness Month
May is once again Invasive Species Awareness Month in Illinois. This statewide effort is held each year to educate and inform citizens about the threat of invasive species. This year's theme is "Preserving Illinois' Wild Side." Invasive species impact the wildlands and natural areas of Illinois. Together we can help protect these beautiful and important areas.
Is It Crabgrass or Something Else?
Crabgrass will be germinating soon if it hasn't already. Often times, we find that crabgrass is cursed by gardeners even when it's another grassy weed species that is really to blame. Poor crabgrass. It's the one grassy weed name that many homeowners and gardeners alike know, unfortunately. Of course improper identification can lead to improper control methods...and a remaining weed problem.
Scouting for Cankers
We've been seeing a lot of cankers at the Plant Clinic recently. Cankers are localized areas of dead tissue, and they show up on stems, trunks, and branches. Cankers can be sunken or swollen, and may bleed (or ooze) sap. The bark may be split or cracked. The term "canker" describes a symptom; there can be many causes, including fungi, bacteria, and mechanical damage. Fungal and bacterial cankers tend to show up on stressed trees.