HOW DO YOU TREAT INSECT DISEASES FOR LAUREL PLANTS?
Laurels, 7 years, 3.5-4 ft high Problem first noted three years ago. Bark affected by scale and folilage by shot hole. They change with some treatment but now more white scale on bark. Full sun. No soil problems. Bonide systemic; one last year Bonide tree and shrub for leaves Bayer 3 in 1 for foilage.
This is white prunicola scale, a common pest of cherry laurel. At this time of year, use a stiff-bristled brush (not wire) to knock off as many of the scales as you can. This will also rip the covers off the scale, exposing its body underneath to pesticide spray. Then spray with a dormant oil spray.
If you see tiny, salmon-colored crawlers (which is the juvenile form of this insect) in June, then spray again with insecticidal oil or soap.
Keep you shrub as healthy as you can. This means watering it in a serious drought. It does NOT mean overfertilizing, which makes plants more attractive to insects. Spread mulch or compost around the base of the plant to feed it. Organic amendments like these break down more slowly and feed it more naturally. Also, be sure mulch is not more that 2" deep and never is touching or piled on the base of the trunk.
Here is more info on scale: http://extension.umd.edu/hgic/armored-and-soft-scales-trees-and-shrubs
Here is help for cherry shot hole fungus:
Cherry laurels are susceptible to many leaf spot diseases. One is commonly called ‘shot hole’ because the infected tissue dries up and falls out causing the tiny holes you describe. Mild, wet spring and early summer weather promotes this leaf spot. Rake up and dispose of infected leaves that fall off the plants. The disease is not serious but causes cosmetic damage. Spraying with a fungicide is not practical as the spraying regiment begins when the new leaves emerge and continues every two weeks or so throughout the summer.
for shot hole, will Bayer 3 and 1 work? spay every two weeks?
No, we would not recommend this treatment. Bayer 3 in 1 contains three different chemicals, one of which can be hazardous to bees and other pollinators. You don't need this mixture for what you have going on. We always recommend the least toxic alternative for controls to protect people and the environment.