Q.What Is Eating the Leaves of My Knock Out Roses
My knock out roses are 2 years old. Last year they were beautiful. This year the leaves have holes in the and black spots. One of the bushes has almost lost all of its leaves. I have sprayed and fertilized with no positive results.
Well you could actually have two things going on with your roses. You could have some Black Spot fungus attacking them and you could have something called Bud worms attacking them. The like the buds the best but will eat the foliage as well. For Black Spot that has taken hold strongly, the roses need to be sprayed with a fungicide called Mancozeb. It is applied at 7 to 10 day intervals for three spraying cycles minimum. It will leave a yellowish powder on the foliage but that is part of how it works. It will stop the black spot in its tracks. The Mancozeb is available on-line at http://www.rosemania.com . Tell them Stan the Roseman sent you if you like. The bud worms or other similar worms/caterpillars will require spraying the rosebushes with an insecticide such as Bug B Gon Max. If that does not work then using Sevin might be in order. I would spray for the worms first, then spray for the black spot. Make sure the rosebushes are well watered before applying any of the sprays. Let me know how things go. If it persists, take pictures and send them to me so I can see more what the damage looks like.
Stan the Roseman
Consulting Rosarian
Gardening Know How
