Knowledgebase
Dying Portuguese laurels #879143
Asked July 28, 2024, 6:00 PM EDT
Several of my 5 year old Portuguese laurels have died over the past year. (I still have 2 healthy ones.). The leaves turned yellow and started dropping off. The landscaper thinks maybe there are wire worms in the soil. How do I treat the soil to get rid of whatever it is? How do I keep it from spreading to healthy plants?
Jackson County Oregon
Expert Response
Powdery Mildew. This is a fungal Laurel hedging disease that appears as a white powdery coating on the surface of the leaves. As the fungus develops, the underlying leaf tissue will turn brown and die and the young leaves can often be left with holes, brown patches and ‘tatty’ edges to them. These symptoms can make Laurel hedge plants look more like they have been attacked by pests than a disease.
Vine Weevils: These six-legged black insects are a menace all year round – the mature weevils attack the leaves throughout summer and autumn, and the young grubs eat away at the root system through winter. Biological control such as nematodes can be used, and make sure to only use them as directed. You could also encourage natural predators like birds, nematodes, shrews and hedgehogs, which will also improve the biodiversity of your garden.