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Rununculus disease
Rununculus disease  
I am a gardening enthusiast and have mostly potted flowering plants.I live in North Indian city, Chandigarh.The weather here is extreme.Nowadays its beginning of summer and temp.min is 15 deg celius and max 22 deg C.I have potted Rununculus which is showing wilting, yellowing of leaves and a peculiar whitish coating on leaves.I carefully examined the underside of leaves but couldnt find any mites or spiders.Looks like dewy coating which is easily removable if I wipe the leaves.Please diagnose the condition and advise possible remedies.
Warm regards
Shailesh Mehta

Dear Shailesh, Sorry to make you wait for my answer, but your Rununculus has powdery mildew, a fungal disease which is easily treatable.  Your photograph is excellent.  To get rid of this, you should spray with a lightweight horticultural oil (do not use cooking oil).  You should be able to find this at a gardening supply store.  Spray the plants thoroughly, and then when they dry, the mildew will peel off the plant and flake away.  Now if for some reason you are unable to find horticultural oil, then I would spray the plants with NEEM.  NEEM is an active ingredient in organic pesticides and comes from the NEEM tree which is native to India, so I know it will be available to you.  NEEM is wonderful to have on hand because it will treat insects, mites, and fungus, so it is great when you aren't sure what is causing the damage.  Either chemical will get rid of the powdery mildew.  Now I will warn you that any flowers sprayed will probably get soaked and be ruined, but the plant will regain its health and put out more blooms.  To prevent the powdery mildew, be sure to have good air circulation around your plants, never leave water standing in trays under the plant, and perhaps reduce the moisture a bit.  I hope this information helps, and please write back if you have more questions.  Good luck, Melissa

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Melissa Johnston


Plant diseases, landscaping, tropical plants, roses, herbs, plant care, grafting, horticulture, plant identification, anything about plants I can likely answer.


35 years experience in various plant businesses, 1984 Certified Texas Master Gardener.

Master Gardener Association of Texas charter member

none as of yet, but I have a plant q&a book I am in process of submitting.

Magna cum laude graduate of Texas A&M, 1978

Awards and Honors
Plant growing awards, highest grade for Texas Master Gardener graduates.

Past/Present Clients
Past member of and was very highly rated. Owned landscape company in the past, Almost Paradise, and was very successful despite little equipment, no help, and no advertising. Lived well for two years until 9/11.

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