Boxwood for Laura Part 2 - Ask Extension
Follow up from pics that didn’t send
Knowledgebase
Boxwood for Laura Part 2 #869766
Asked May 23, 2024, 11:45 AM EDT
Follow up from pics that didn’t send
Oakland County Michigan
Expert Response
Thanks for the additional pictures. This appears to be boxwood leafminer. Open a few leaves and see if any larvae are still present( see leafminer link below for pictures and treatment)
Here is information on how to treat leafminers.
https://www.canr.msu.edu/news/boxwood_leafminer_a_serious_pest_of_a_favorite_landscape_plant
If it were boxwoodblight, the stems would blacken and he leaves would easily drop off leaving bare stems. Here is an article about boxwood blight, so you can watch for it in future-
https://www.extension.purdue.edu/extmedia/bp/bp-203-w.pdf
Please read and follow all instructions and safety precautions found on the label before using any pesticide.
Here is information on how to treat leafminers.
https://www.canr.msu.edu/news/boxwood_leafminer_a_serious_pest_of_a_favorite_landscape_plant
If it were boxwoodblight, the stems would blacken and he leaves would easily drop off leaving bare stems. Here is an article about boxwood blight, so you can watch for it in future-
https://www.extension.purdue.edu/extmedia/bp/bp-203-w.pdf
Please read and follow all instructions and safety precautions found on the label before using any pesticide.
Two final questions about leaf miner:
1) can you recommend varieties of boxwood least susceptible to leaf miner?
2) we’re going to replace our severely diseased plants. Can we plant new boxwood in their place and what special preparation of the soil or pre-treatment of the new boxwoods would you recommend?
Thank you very much!
Leafminer is cosmetic and can be controlled with treatment. There are resistant cultivars-
(From https://ag.umass.edu/landscape/fact-sheets/boxwood-leafminer )
“When planting new boxwoods, choose more resistant varieties to minimize the effects of boxwood leafminer. Varieties with more resistance include, but may not be limited to:
However, there are some boxwood that are less affected if/when blight becomes an issue. I would recommend that you choose a species that is less affected by boxwood blight if you are going to replace the hedge.
Here is an article that lists some boxwoods known to be less affected,— https://ext.vt.edu/content/dam/ext_vt_edu/boxwoodblighttaskforce/files/resistant_susceptible.pdf
To replant in the same place you will need to dig as much of the large roots and trunks out as possible. Clean up as much debris as you can —the tiny leaves the twigs etc., to help minimize the presence of pests and disease left behind.
(From https://ag.umass.edu/landscape/fact-sheets/boxwood-leafminer )
“When planting new boxwoods, choose more resistant varieties to minimize the effects of boxwood leafminer. Varieties with more resistance include, but may not be limited to:
- Buxus microphylla var. japonica
- Buxus microphylla ‘Green pillow’, ‘Grace Hendrick Phillips’
- Buxus microphylla var. sinica ‘Franklin’s Gem’
- Buxus sempervirens ‘Pendula’, ‘Argenteo-variegata’, ‘Handworthiensis’, ‘Pyramidalis’, ‘Suffruticosa’, ‘Vardar Valley’, ‘Justin Brouwers’
- Buxus harlandii ‘Richard’
- Buxus sinica var. insularis ‘Nana’
Heavily pruning (if practical) all first-year growth (by pruning branches back about ⅓ of their length) after egg-laying in June will remove infested leaves. Destroy clippings and do not dispose of near plants.”
The bigger concern is boxwood blight, to which all boxwood are susceptible and there currently is no treatment for boxwood blight.However, there are some boxwood that are less affected if/when blight becomes an issue. I would recommend that you choose a species that is less affected by boxwood blight if you are going to replace the hedge.
Here is an article that lists some boxwoods known to be less affected,— https://ext.vt.edu/content/dam/ext_vt_edu/boxwoodblighttaskforce/files/resistant_susceptible.pdf
To replant in the same place you will need to dig as much of the large roots and trunks out as possible. Clean up as much debris as you can —the tiny leaves the twigs etc., to help minimize the presence of pests and disease left behind.
