Sick crab apple tree - Ask Extension
The crab apple tree is 10-12 years old. The problem has been a low-grade problem for a few years.
Condition has worsened every year.
100% of the ...
Knowledgebase
Sick crab apple tree #878870
Asked July 26, 2024, 11:09 AM EDT
The crab apple tree is 10-12 years old. The problem has been a low-grade problem for a few years.
Condition has worsened every year.
100% of the tree affected.
Tree seems fine in spring, but by mid- summer most leaves are dead and falling off.
A few berries formed, but didn't develop well.
Lichens on trunk, could this be the problem?
Any recommendations or diagnosis?
Livingston County Michigan
Expert Response
Good Morning,
Looks like the fungus, Venturia inaequalis, known as apple scab, is a leaf spot disease that can cause serious leaf drop on susceptible crabapple trees. See attached
Why is my crabapple tree losing leaves? - MSU Extension
Lichens are actually two organisms, a fungi and algae. The two organisms occur together and form a symbiotic, or mutually beneficial, relationship. The fungi provide protection and a place for algae to live while the algae provide energy via photosynthesis. There are thousands of types of lichens made up of various fungi and algae, and some types of cyanobacteria.
What are lichens and what are they doing on my tree? - MSU Extension
You can submit a sample for a small fee for a positive diagnosis.
Submit Samples - Plant & Pest Diagnostics (msu.edu)
I hope this helps. Thanks for using our service.
Looks like the fungus, Venturia inaequalis, known as apple scab, is a leaf spot disease that can cause serious leaf drop on susceptible crabapple trees. See attached
Why is my crabapple tree losing leaves? - MSU Extension
Lichens are actually two organisms, a fungi and algae. The two organisms occur together and form a symbiotic, or mutually beneficial, relationship. The fungi provide protection and a place for algae to live while the algae provide energy via photosynthesis. There are thousands of types of lichens made up of various fungi and algae, and some types of cyanobacteria.
What are lichens and what are they doing on my tree? - MSU Extension
You can submit a sample for a small fee for a positive diagnosis.
Submit Samples - Plant & Pest Diagnostics (msu.edu)
I hope this helps. Thanks for using our service.
Good morning,
Could annual injections cure this disease?
I contacted a tree service (Safari) and he said he could inject for Apple scab after Aug 14 and it would be good for a year.
He also stated that the Magnolia scale that two of my trees have could be injected anytime after May.
You didn't mention anything about injections, are they worthwhile and effective? I have a dog and a horse so prefer not to spray, also would be much easier if one annual injection could be effective. I don't know what chemical name they intend to use.
Barb Seidl
Good Morning,
I found this information on treatment.
Control varied among canopy organs due to different transpiration, with best scab control on shoots, fruit, and then spurs. Good scab control is provided by 2-3 spring injections. Residues of synthetic fungicides in fruit were always below the residue tolerances. Fall injection did not improve apple scab control. To get temporally uniform imidacloprid distribution in the crown, best results were achieved by injection dose delivery at 4 times, 14 days apart.
Apple scab of apples and crabapples | UMN Extension
1.DissertationSrdjanAcimovicMSU2014.pdf
Disease management in apples using trunk injection delivery of plant protective compounds (msu.edu)
When dealing with soft scale species such as the magnolia scale, you can use a systemic treatment of imidacloprid (Bayer Tree & Shrub is one possible trade name) or dinotefuran (Orthro Tree & Shrub is one possible trade name). A systemic insecticide helps to give you control without reliance on broadcast sprays on the plant. This helps keep insecticide residues contained within the plant you wish to protect and helps to ensure the product will affect the pests you are targeting. Timing is important when choosing to use a systemic product though. An application of imidacloprid in May, after flower petals have fallen from the tree, will provide protection. For dinotefuran, applications can be made in August to provide control the next year.
Magnolia Scale | Entomology (uky.edu)
I hope this helps.
I found this information on treatment.
Control varied among canopy organs due to different transpiration, with best scab control on shoots, fruit, and then spurs. Good scab control is provided by 2-3 spring injections. Residues of synthetic fungicides in fruit were always below the residue tolerances. Fall injection did not improve apple scab control. To get temporally uniform imidacloprid distribution in the crown, best results were achieved by injection dose delivery at 4 times, 14 days apart.
Apple scab of apples and crabapples | UMN Extension
1.DissertationSrdjanAcimovicMSU2014.pdf
Disease management in apples using trunk injection delivery of plant protective compounds (msu.edu)
When dealing with soft scale species such as the magnolia scale, you can use a systemic treatment of imidacloprid (Bayer Tree & Shrub is one possible trade name) or dinotefuran (Orthro Tree & Shrub is one possible trade name). A systemic insecticide helps to give you control without reliance on broadcast sprays on the plant. This helps keep insecticide residues contained within the plant you wish to protect and helps to ensure the product will affect the pests you are targeting. Timing is important when choosing to use a systemic product though. An application of imidacloprid in May, after flower petals have fallen from the tree, will provide protection. For dinotefuran, applications can be made in August to provide control the next year.
Magnolia Scale | Entomology (uky.edu)
I hope this helps.
Thank you so much for the info!
You're welcome. Good Luck!
