Rose Bush Beatles
I have what appear to be "beatles" eating my roses and also the leaves just unter the rose flowers. The "beatles" are about 1/2 inch long and are dark colored. I have seen them fly but it is rare. I've tries powders, sprays, and systemic feedings with out success. Any suggestions would be a great help. Thank you.
PS My neighbor has the same problem.
Arapahoe County Colorado
Japanese Beetle (JB) feeds preferentially on rose petals and leaves of linden, bean, grape, Virginia Creeper, raspberry. JB can feed on leaves of about 425 plants, many of which grow in the Denver area.
Japanese Beetles are difficult to control, and are a major plant pest in many US States.
The JB adults you see flew in from elsewhere...so treating your lawn to kill JB grubs (larvae) will have very little - if any - discernible impact on the number of JB adults found in your yard later. This also means that your attempts to get rid of them won't be permanent.
Pheromone traps catch many JB adults (and that is a pretty satisfying way to get some revenge), BUT usually attract many more JB adults to an area than would have arrived there without traps.
Insecticide applications must be made in consideration of how they may affect bees visiting flowers...roses, for example.
More details and control options at http://extension.colostate.edu/topic-areas/insects/japanese-beetle-5-601/