boxwood damage, leaf minor? - Ask Extension
I am having a problem with my american boxwood where I notice pieces of box leaf around the base of many of my boxwood. I have sprayed with malathion ...
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boxwood damage, leaf minor? #682409
Asked March 02, 2021, 6:01 PM EST
I am having a problem with my american boxwood where I notice pieces of box leaf around the base of many of my boxwood. I have sprayed with malathion but but not at the best time of year. I am not sure that malathion is the best thing to use. Can you tell me what the issue is with my box and what insecticide would be best to use. thank you
Richmond County Virginia
Expert Response
Leaf miners do not cause leaf drop. So there is some other problem. I am not able to get a clear view in the pictures you submitted. It does look like you may have leaf miners. While malathion is a recommended chemical for treatment of leaf miner, you would spray in April or early May when the adults are active.
Could you send me some better pictures. I've attached a document on how to take good digital images for evaluation. The example used in the document is a boxwood and looking for symptoms of Boxwood Blight. That is what I would like for you to try and submit images of.
Could you send me some better pictures. I've attached a document on how to take good digital images for evaluation. The example used in the document is a boxwood and looking for symptoms of Boxwood Blight. That is what I would like for you to try and submit images of.
Thank you. I have attached 3 pictures per your suggestion. Randy Robins
On Mar 3, 2021, at 10:34 AM, Ask Extension <<personal data hidden>> wrote:
Definitely see leaf miners in the first picture. So treatment of malathion in April and May when the adults are active.
I do not see signs of boxwood blight in the images submitted.
You indicated that you sprayed with malathion, but not the best time of the year. When did you spray it? Did you notice the dropped leaves before or after you sprayed.
Also, the plants look pretty tight, when did you last prune them?
I do not see signs of boxwood blight in the images submitted.
You indicated that you sprayed with malathion, but not the best time of the year. When did you spray it? Did you notice the dropped leaves before or after you sprayed.
Also, the plants look pretty tight, when did you last prune them?
I sprayed when I saw leaves on the ground which was fall and winter. i will spray again in april and may. I missed spray spring of 2020 hence my problem with bad infestation. May look for alternative to malathion. thanks for your help.
On Mar 4, 2021, at 4:29 PM, Ask Extension <<personal data hidden>> wrote:
Our recommendations from our entomologist on control of leaf miners in boxwood is found in our Home and Grounds Pest Management Guide found here: https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/456/456-018/ENTO-336.pdf . The recommendations are on page 4-47. (I'm sorry, this system will not allow me to cut and paste the section.)
While Malathion is a recommendation, it is only effective on the adults. And the adults are flying, so control can be difficult. A better chemical choice may be Imidacloprid. This is a systemic chemical which is translocated through the entire plant and will kill the miners in the leaves. Apply per label directions. You will likely need to do a follow-up application again next spring for complete control.
While Malathion is a recommendation, it is only effective on the adults. And the adults are flying, so control can be difficult. A better chemical choice may be Imidacloprid. This is a systemic chemical which is translocated through the entire plant and will kill the miners in the leaves. Apply per label directions. You will likely need to do a follow-up application again next spring for complete control.
