Otto Luken dieing
There is something killing my Prunus Laur. Otto Luken Dwarf Cherry Laurel and it is continuing inspire of spraying it for the last several months with Bayer Insect,Disease,& Mite Control that was recommended by Homestead Gardens. Please the the white little bumps on the branch in the attached photo. What should I do? Thanks!
Anne Arundel County Maryland
This is white prunicola scale which occurs on cherry laurel and flowering cherry, too. Scales are insects with protective covers like a turtle shell. When the shrub is dormant (winter), use a stiff-bristled brush (not wire) to knock off as many of the scales as you can. This also serves to rip the covers off the scale, exposing the scale’s body underneath to pesticide spray. Spray with a dormant oil.
If you see the tiny salmon-colored crawlers (juveniles) in June, spray with insecticidal oil or soap.
Keep your 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
I brushed them off the other day and then sprayed with dormant oil today. Should I repeat the oil spray in a month or two?
No. Watch closely, and as noted above, spray again only if you see salmon-colored crawlers in June.