Scale infestation on Meyer Lemon drawft tree - Ask Extension
I have a Meyer Lemon Tree that is not quite a year old but has many fruit on it. As I observed the leaves beginning to deform I saw the plant had deve...
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Scale infestation on Meyer Lemon drawft tree #837428
Asked June 25, 2023, 12:04 PM EDT
I have a Meyer Lemon Tree that is not quite a year old but has many fruit on it. As I observed the leaves beginning to deform I saw the plant had developed scale. I hand picked the scale and have bathed the plant in Neem oil twice. Each morning when I come out I still find scale. Some leaves are starting to show a black fungus and I am cleaning that off with a soft brush.
Will the scale ever go away or will I be tending to it daily to keep it alive?
Thank you!
Bill
Marion County Oregon
Expert Response
Dear Bill,
Thank you for contacting Ask Extension about scale insects on your Meyer lemon tree. Scale is extremely common on citrus plants and they usually arrive in the same pot. Scale is pervasive, but once under control, it can be kept in check with only occasional spraying as soon as they begin to reappear.
Horticultural oils and insecticidal soaps are the only options for control of brown soft scale when food crop plants are grown indoors. Note that systemic insecticides containing imidacloprid are not approved for use on food crop plants.
Horticultural oils may be either mineral oils or neem seed oils. They are designed to be mixed with water (1-2% concentration) and sprayed directly on the body of the insect. These oils kill primarily by smothering, blocking the small openings through which the insect breathes.
A single application of horticultural oil cannot kill crawlers that remain protected under their cover. To be effective, oil sprays need to be repeated several times. The best way is to take the plant outdoors and spray from top to bottom, bottom to top, on both sides of the leaves.
I'd like to mention that neem is commonly used because home gardeners believe it is "safe". However, neem may adversely affect children, pets, aquatic species, and beneficial insects. Please refer to
http://npic.orst.edu/factsheets/neemgen.html#:~:text=Neem%20oil%20is%20made%20of,to%20grow%20and%20lay%20eggs.
Insecticidal soaps are made from potassium salts of fatty acids. They can be used as dilute sprays and are usually very effective against first-stage crawlers. Insecticidal soaps only kill insects directly covered during application. Treatment must be reapplied to kill the insects that were not exposed during the first application, including late-hatching crawlers.
I hope this information is helpful. If you have other questions, please write again.
Thank you for contacting Ask Extension about scale insects on your Meyer lemon tree. Scale is extremely common on citrus plants and they usually arrive in the same pot. Scale is pervasive, but once under control, it can be kept in check with only occasional spraying as soon as they begin to reappear.
Horticultural oils and insecticidal soaps are the only options for control of brown soft scale when food crop plants are grown indoors. Note that systemic insecticides containing imidacloprid are not approved for use on food crop plants.
Horticultural oils may be either mineral oils or neem seed oils. They are designed to be mixed with water (1-2% concentration) and sprayed directly on the body of the insect. These oils kill primarily by smothering, blocking the small openings through which the insect breathes.
A single application of horticultural oil cannot kill crawlers that remain protected under their cover. To be effective, oil sprays need to be repeated several times. The best way is to take the plant outdoors and spray from top to bottom, bottom to top, on both sides of the leaves.
I'd like to mention that neem is commonly used because home gardeners believe it is "safe". However, neem may adversely affect children, pets, aquatic species, and beneficial insects. Please refer to
http://npic.orst.edu/factsheets/neemgen.html#:~:text=Neem%20oil%20is%20made%20of,to%20grow%20and%20lay%20eggs.
Insecticidal soaps are made from potassium salts of fatty acids. They can be used as dilute sprays and are usually very effective against first-stage crawlers. Insecticidal soaps only kill insects directly covered during application. Treatment must be reapplied to kill the insects that were not exposed during the first application, including late-hatching crawlers.
I hope this information is helpful. If you have other questions, please write again.
Hi Lynne,
Thank you for your prompt reply. This is all great information!
One question, I had a nursery person tell me to try to find 100% Neem Oil as the sprays only contain a small amount of Neem Oil. I found a product with 70% Neem Oil but was wondering if too much could harm the plant?
Thanks,
Bill
On Jun 26, 2023, at 1:26 PM, Ask Extension <<personal data hidden>> wrote:
Dear Bill,
Thanks for the question about neem oil. The problem with homemade pesticides is that they have not been tested for specific horticultural uses. (For this reason, it is not approved for horticultural use in Canada.) Neem can contain a number of ingredients, however, products that contain azadirachtin will be most effective because it impedes insect feeding and growth.
Neem oil and some of its purified components are used in over 100 pesticide products. I suggest you look for a neem product that is actually registered by the EPA as an insecticide. Registered products must be labeled with instructions on how and when to use them, safety precautions, active ingredients, and which plants and pests the product is formulated for. Always read and follow label instructions carefully.
Here is the registration for one neem product, but it is by no means the only one. Your local greenhouse supply should be able to help you locate what you are looking for.
https://www3.epa.gov/pesticides/chem_search/ppls/<personal data hidden>1-20200106.pdf
I hope this is useful to you.
Thanks for the question about neem oil. The problem with homemade pesticides is that they have not been tested for specific horticultural uses. (For this reason, it is not approved for horticultural use in Canada.) Neem can contain a number of ingredients, however, products that contain azadirachtin will be most effective because it impedes insect feeding and growth.
Neem oil and some of its purified components are used in over 100 pesticide products. I suggest you look for a neem product that is actually registered by the EPA as an insecticide. Registered products must be labeled with instructions on how and when to use them, safety precautions, active ingredients, and which plants and pests the product is formulated for. Always read and follow label instructions carefully.
Here is the registration for one neem product, but it is by no means the only one. Your local greenhouse supply should be able to help you locate what you are looking for.
https://www3.epa.gov/pesticides/chem_search/ppls/<personal data hidden>1-20200106.pdf
I hope this is useful to you.
Wow!, you guys are good!
Thank you!
Bill
On Jun 26, 2023, at 4:19 PM, Ask Extension <<personal data hidden>> wrote:
