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vitrsna

Euphorbia leaf disease

11 years ago

Greetings Garden Clinic...I am in zone 11, humid half of the year and dry the other half. I have a Euphorbia (Dalechampia dioscoreifolia) vine with a terrible case of something. Almost all of the leaves are infected as shown below. The greenest leaf to the left is how a healthy leaf should look although there are signs that it too is becoming infected. I would very much like to save this vine. The white of the affected leaves does not rub or brush off and doesn't seem to have a texture of its own. Can anyone identify this disease? I have not noticed any bugs on the vine that might be responsible. Thanks for your input.


Comments (4)

  • 11 years ago

    Beverly, the manner in which the condition appears to follow the leaf veins, suggests a sap-sucking organism. I would dampen a white paper towel with a strong soap solution and wipe the leaf surface firmly. If there is a discoloration, especially yellow(ish), on the towel, it would strongly indicate a soft or hard scale-insect. Do the same for the underside of the leaves

  • 11 years ago

    Thank you ronalawn, I did as you suggested but using a clean white cloth. Yes, the cloth did turn yellowish but the process did not "clean" the top part of the leaf completely. The underside of the leaf does not have the same pattern of white as the top part of the leaf, but there were 2 tiny black dots that came off with the scrubbing that possibly could be the perpetrators? This is a 10' (3 m) tall vine. I am thinking i will have to cut it all the way back. I took some cuttings to start new plants from some uninfected parts of the vine but it is doubtful that the cuttings will be successful at this time of year. Do the soft/hard scale insects come from above ground? Or do you think the little buggers have infected the roots as well? Do you think i can save the vine by digging up the roots and replanting them elsewhere? Adjacent plants are not infected. My pest control methods are organic only. Are there certain environmental conditions that make a plant susceptible to this type of disease (like too much water, not enough water, etc)? Any suggestions that you might have would be sincerely appreciated.


  • 11 years ago

    vitrsna, please apologize to your mom if she did not name you 'Beverly'.

    Check out this link and examine the image to the far right in the top row. That adult is neither a hard nor soft scale. Yet the leaf surface appears peppered with the white stuff. They might be eggs. I really cannot tell. (I used to doze a lot during entomology classes).

    I am going to stick with hard scale and recommend applications of oil. Please follow all the directions. I have limited experience with the method; but things can go wrong - I have been told. This second link might help.

    Mealy bugs were my nemesis on indoor plants; they can be washed off or pruned away. Hard scales were controlled by using a systemic insecticide. These products get into the plant system and will effectively dispatch the sucking insects over time. It does not qualify as an organic treatment IMHO but the chemical group has been associated with the decline of bees - outdoors! I cannot see any adverse effect when it is applied indoors; but I still am prone to dozing. The hard scales seldom move in the adult stage; but the go through a 'crawler' stage and that is when the oil will get them. In my experience hard scale indoors has always been introduced indoors; usually on that recently acquired addition.

    And now you know as much as I do on this subject. But if you think that further correspondence will help, by all means, continue.

    Cheers!

  • 11 years ago

    :-D Thank you ronalawn! I have cut the vine to a few inches above the ground and disposed of all the infected foliage, and washed my gloves and tools. I have also washed well with soapy water and cinnamon oil what remains of my vine. I have also cleared all of the soil and mulch around the base of the plant. I have germinated new seedlings and am preparing to dig up the roots of my pruned plant and move it to a different location. The White oil is out of the question. This is a host plant for some butterflies. It originally took me 3 years to find viable seeds to grow this unique and much loved vine. It is not available in nurseries where i live. I was so happy to find some seeds i had saved from 2014 in case my transplant is not successful. The vine will grow quickly in the heat and humidity. I will keep a backup plant in a container in case this should occur in the future. So i think i am good for now. Early detection is a must so i will be more observant in the future. I appreciate your efforts on my behalf. Actually, I have moved from Gardenweb to another garden forum site that suits me much better, so i won't be "bugging" you in the future :-D Happy gardening!