Disease on evergreen holly
I have a row of evergreen holly called ilex hollies. The original bushes have been there 10 years. A disease of some type comes out periodically. A healthy bush has leaves that turn brown then a whole section dies. I don't see any bugs. I have sprayed the bushes with Fung-oil", but it keeps coming back. What can I use to get rid of this disease? Thank you in advance.
Howard County Maryland
Based on your photos you may be dealing with several issues. These hollies can be susceptible to a root rot due to poor drainage and heavy soils. Do you have a sprinkler system or water on a schedule? If so, this can affect the root system of the plants. Make sure the soil drains well and there are no drainage spouts nearby dumping water into the area. Keep mulch no thicker than two inches in depth and away from the base of the stems.
Also, look for evidence of voles which are Meadow mice that feed on the roots of trees, shrubs, and herbaceous plants. Look for silver dollar sized holes in the mulch and around the base of the plants and trap with mouse traps if need be.
.At this point, prune out any dead plant material on the shrubs. Make sure the soil drains well. If not, you will have to correct this.