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Plant Diseases/Dahlia leaves ? Pest/disease


Dahlia leaves
Dahlia leaves  
Hi, my dahlias that are currently 1 ft high are suffering from a problem affecting their leaves. As the leaves are growing ( tuber came out of dormancy 3 months ago so hasn't flowerd yet ) they are alot smaller and some are crinkled and a little twisted. They are green with the occasional fading of little spots on the leaf. I initially thought it was damage from a heat wave we just had ( 3 weeks of over 100 degrees ) when the plants had wilted a little although it is affecting some dahlias and not others. These are new dahlia tubers I have planted this season. Climate consists of long hot summers and short freezing winters and continuos drought ( I am in Australia after all ). Any help would be appreciated. Thankyou !


These symptoms may be caused by one of two things. Some herbicide chemicals (weed killers) that come in contact with the leaves (direct contact or drift onto the leaves). Or, secondly, this may be a virus that infected the plant. Virus symptoms can easily be confused with many other things

If it was a chemical, often the plant may grow "out of the problem". Watch the newer leaves to see if they start to look normal over time.  Also if it is a chemical, nearby dahlias should be affected as well.  Sometimes this can be a clue that it is a chemical rather than a bona fide disease.

If it is a virus, the plant will have the virus for the rest of its life.  Sorry, no cure for an infected plant.  Replacing the plant with a healthy one is the best option.  To confirm positively if this is a virus, the plant would have to be tested in a lab.

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Dr Stephen Vann


Plant Diseases and Disorders of Lawn Grasses, Trees, Vegetables,and Ornamentals


Plant Diseases Identification and Management

B.S. Botany --- Miss. State Univ. M.S. Plant Pathology --- Miss. State Univ. Ph.D. Plant Pathology --- Texas A & M Univ.

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