Question
I have two knockout roses I planted about one month ago and they were looking very healthy and thriving.  Tent worms got after them and chewed holes.  I sprinkled 7-dust on them and a few days later, they looked worse than before I sprinkled it on.  They are blooming but the blooms are "floppy"  and weak looking and the leaves are more yellow and brown with more holes.  Is 7-dust bad for new roses?  Is there hope for a healthy rose this year?

Answer
Sevin is an insecticide and used as directed, shouldn't damage the roses.  You usually sprinkle it all around the base of the rose because that is where the bugs go after eating. Do you think it could be possible you may have used too much on the rose leaves? Brown on leaves usually means they were burnt be a chemical.  I would cut the roses down and make them start out again.  Water well to dilute the Sevin lying around in case there is too much of it. If that is the problem then the roses will start to grow new growth that is healthy. If they still continue to look sad, the problem will be in the roots. The other alternative could be you were sold sick plants. Use an organic spray on the caterpillars as they are easy to kill and don't need something expensive to get rid of them. Safers Trounce is a good one.