TALL PHLOX LOOKS BAD! - Ask Extension
My Tall Phlox looks terrible. Help, please? What is wrong with it and what should I do to fix/help it? I have 4-5 plants- all with varying degrees of ...
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TALL PHLOX LOOKS BAD! #194589
Asked June 26, 2014, 3:34 PM EDT
My Tall Phlox looks terrible. Help, please? What is wrong with it and what should I do to fix/help it? I have 4-5 plants- all with varying degrees of this problem. This one is about the worst:
Wayne County Michigan
Expert Response
Hello,
This looks like spider mite damage. Spider mites are active in hot, dry conditions. If your phlox are located in such an area- such as being planted near a sunny wall where the heat reflects back onto the plant, this could be your culprit.
Here is a short description of spider mites- “Phlox is free of insect pests but may get infested with spider mites during hot dry weather. You will first probably notice that the leaves are turning yellow with lots of little tiny yellow dots on the leaves. Try tapping some leaves over a piece of paper to see if the mites are visible as they slowly move on the paper. A hand lens can also be used to make it easier to see the mites and minute webs they make on the underside of the leaves. If you have a mite problem, look for some miticides or insecticides that will also control mites to treat the plants. It is important to get good coverage of the undersides of the leaves because that is where they are most commonly found. I like to use an insecticidal soap or oils that are labeled for use on herbaceous ornamentals during the growing season.”
And, here is a link with more information_
http://ohioline.osu.edu/hyg-fact/2000/pdf/2012.pdf
If you check for spider mites and do not think this is the problem, there are a number of leaf spotting diseases that affect phlox. This description comes from NSDU Extension-.
“Phlox are subject to a number of what I call "high humidity" diseases—powdery and downy mildew, leaf spots and stem blights. Control these diseases by cutting back the frosted stems this fall and removing them. As new growth emerges next spring, keep a wary eye out for any development of the mildew and dust with sulfur or other appropriate fungicide. Sometimes increasing the spacing between the plants helps cut down on the spread of the disease, along with a reduction in overhead watering”.
To reduce fungal diseases you can also mulch around the plants to prevent splashing when watering or when it rains. Spray healthy foliage with garden sulfur fungicide according to label directions to prevent the spread of the fungus. Spraying already infected foliage won’t ‘cure’ it, but will keep it from progressing. Get as good coverage as you can- both upper and under sides of leaves. As suggested above, when fungal disease in a humid environment is a problem, be sure to water from underneath – soaker hose is one way – to keep the foliage dry.
To get a more precise diagnosis of a fungal disease you can submit a sample to the MSU Diagnostic Lab. See www.pestid.msu.edu for instructions on how to submit a sample. There is usually a small charge for the service. You may call the lab, first, if you have any questions about their service.
This looks like spider mite damage. Spider mites are active in hot, dry conditions. If your phlox are located in such an area- such as being planted near a sunny wall where the heat reflects back onto the plant, this could be your culprit.
Here is a short description of spider mites- “Phlox is free of insect pests but may get infested with spider mites during hot dry weather. You will first probably notice that the leaves are turning yellow with lots of little tiny yellow dots on the leaves. Try tapping some leaves over a piece of paper to see if the mites are visible as they slowly move on the paper. A hand lens can also be used to make it easier to see the mites and minute webs they make on the underside of the leaves. If you have a mite problem, look for some miticides or insecticides that will also control mites to treat the plants. It is important to get good coverage of the undersides of the leaves because that is where they are most commonly found. I like to use an insecticidal soap or oils that are labeled for use on herbaceous ornamentals during the growing season.”
And, here is a link with more information_
http://ohioline.osu.edu/hyg-fact/2000/pdf/2012.pdf
If you check for spider mites and do not think this is the problem, there are a number of leaf spotting diseases that affect phlox. This description comes from NSDU Extension-.
“Phlox are subject to a number of what I call "high humidity" diseases—powdery and downy mildew, leaf spots and stem blights. Control these diseases by cutting back the frosted stems this fall and removing them. As new growth emerges next spring, keep a wary eye out for any development of the mildew and dust with sulfur or other appropriate fungicide. Sometimes increasing the spacing between the plants helps cut down on the spread of the disease, along with a reduction in overhead watering”.
To reduce fungal diseases you can also mulch around the plants to prevent splashing when watering or when it rains. Spray healthy foliage with garden sulfur fungicide according to label directions to prevent the spread of the fungus. Spraying already infected foliage won’t ‘cure’ it, but will keep it from progressing. Get as good coverage as you can- both upper and under sides of leaves. As suggested above, when fungal disease in a humid environment is a problem, be sure to water from underneath – soaker hose is one way – to keep the foliage dry.
To get a more precise diagnosis of a fungal disease you can submit a sample to the MSU Diagnostic Lab. See www.pestid.msu.edu for instructions on how to submit a sample. There is usually a small charge for the service. You may call the lab, first, if you have any questions about their service.
