Redtip Photinia

Question

I have large redtip photinias that are losing their leaves and dying. There is something on the ground around the trunks that resembles red sawdust. We have a number of these plants (10) and the others are doing well. The plants are trimmed and I could not find signs of the fungus on the leaves. What could this be? There looks to be some small bore holes along the trunk. Any suggestions?

Answer 1

It sounds like it has a borer of some kind. Flathead borers are the most common on this plant. This article will help: http://www.ipm.ucdavis.edu/PMG/GARDEN/PLANTS/INVERT/flatheaded.html