Signup to receive email updates
Authors
Recent Posts
Links
Blog Archives
- April 2018 (2)
- March 2018 (5)
- February 2018 (2)
- January 2018 (4)
- December 2017 (4)
- November 2017 (3)
- October 2017 (5)
- September 2017 (4)
- August 2017 (5)
- July 2017 (4)
- June 2017 (4)
- May 2017 (5)
- April 2017 (4)
- March 2017 (5)
- February 2017 (2)
- January 2017 (7)
- December 2016 (3)
- November 2016 (3)
- October 2016 (5)
- September 2016 (4)
- August 2016 (4)
- July 2016 (5)
- June 2016 (4)
- May 2016 (4)
- April 2016 (4)
- March 2016 (3)
- February 2016 (4)
- January 2016 (6)
- December 2015 (3)
- November 2015 (3)
- October 2015 (4)
- September 2015 (4)
- August 2015 (4)
- July 2015 (5)
- June 2015 (4)
- May 2015 (3)
- April 2015 (3)
- March 2015 (3)
- February 2015 (4)
- January 2015 (5)
- December 2014 (4)
- November 2014 (2)
- October 2014 (3)
- September 2014 (4)
- August 2014 (4)
- July 2014 (4)
- June 2014 (3)
- May 2014 (3)
- April 2014 (2)
- March 2014 (2)
- February 2014 (4)
- January 2014 (2)
- December 2013 (4)
- November 2013 (5)
- October 2013 (4)
- September 2013 (3)
- August 2013 (5)
- July 2013 (4)
- June 2013 (4)
- May 2013 (4)
- April 2013 (4)
- March 2013 (4)
- February 2013 (2)
- January 2013 (4)
- December 2012 (4)
- November 2012 (5)
- October 2012 (4)
- September 2012 (3)
- August 2012 (5)
- July 2012 (4)
- June 2012 (4)
- May 2012 (4)
- April 2012 (4)
- March 2012 (6)
- February 2012 (3)
- January 2012 (4)
- October 2011 (1)
- June 2011 (1)
- April 2011 (1)
- January 2011 (1)
- December 2010 (1)
- November 2010 (2)
- October 2010 (1)
- August 2010 (3)
- July 2010 (2)
- June 2010 (2)
- May 2010 (2)
- April 2010 (1)
- March 2010 (1)
- February 2010 (2)
- January 2010 (2)
- December 2009 (2)
- November 2009 (1)
- October 2009 (2)
- September 2009 (1)
- August 2009 (5)
- July 2009 (2)
- June 2009 (2)
- May 2009 (1)
- April 2009 (2)
- January 2007 (1)
335 Total Posts
follow our RSS feed

Wednesday, May 17, 2017
Flowering Crabapple and Apple Tree Diseases
Home orchardists know that to protect their apple trees, sprays are needed from the time buds begin to swell until a bit after flower petals begin to fall. If you have an ornamental flowering crabapple in the landscape, the same protection period applies. While CAR will not kill either the apple or crabapple, it can, over years, weaken the trees and will allow other problems to show up. For the home orchard, CAR-infected apple trees will not be able to produce all the energy needed to fulfill both the apple fruit and create next year's potential flowers and vegetative buds. One simple trick to control potential disease is to remove the galls found on cedars and junipers. That can be done now while easily seen and again in the fall when the spores have returned to the evergreen hosts where they look like a small gray brain on the evergreen branch.
The second and more damaging fungal disease known as Apple scab can both be aesthetically damaging and economically damaging for the home orchard. Apple scab only needs one deciduous host, the apple or crabapple. While CAR causes leaf damage, Apple scab actually causes the foliage to fall off the tree by early- to mid-summer and can disfigure apples too, so the damage to the apple tree is two-fold. There is a loss of leaves so the tree looks as bad as the crabapple, but the bigger part is without leaves the tree cannot produce a quality apple. Apple scab fungus overwinters on fallen leaves and returns to the crabapple or apple tree during the same period as CAR. If trees are being treated for one disease, the other also is treated. Sanitation can help control the disease by removing infected fallen leaves in the fall.
Both diseases are airborne, so sanitation is helpful (removing the CAR galls and raking up fallen AS infected leaves), but since both are spread by spores in the wind, treatments are likely to still be needed. Flowering crabapples can be treated with a fungicide only product. Apple trees are typically treated with a combination product containing a fungicide for leaf diseases and an insecticide for apple tree insects because no one wants to find a worm in an apple. As long as the current weather pattern continues, preventative sprays are needed. As always, read and follow label instructions.
Richard Hentschel is a Horticulture Extension Educator with University of Illinois Extension, serving DuPage, Kane and Kendall counties. Stay tuned to more garden and yard updates with "This Week in the Garden" on Facebook at facebook.com/extensiondkk/videos.