|I have been spraying my roses with insect killer stuff and recently I spreaded some insect killing granuals and I still am getting Japanese beatles on my flowers. I also have black spots on the leaves of the roses and yellowing leaves. What can I do to get rid of these problems?
|Answer from NGA
July 14, 2010
|Sounds like the typical symptoms of black spot, a fungal disease. Black spot can be difficult to control. You might prune away the most obviously diseased stems and leaves to encourage healthy new growth. Since you're dealing with insects along with disease, I'd use a neem oil based product such as Rose Defense. It has some residual qualities so it should control the Japanese beetles as well as the black spot. Be sure to apply according to label directions. Best wishes with your roses!
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