oregon salal blight?

Asked April 24, 2017, 5:06 PM EDT

Hi, i have been noticing a lot of salal around my area, Lakeside, ore. that is turning white. It seems to be killing the plant eventually. I was wondering if anyone else has taken notice and if so what is the info you can give me. Thanks Ed

Coos County Oregon diagnosis of plant problems horticulture

4 Responses

We are not seeing this problem in Lincoln County to my knowledge. I did reassign to our Ag agent in Coos County.
It would be helpful if you could provide a photo and some additional details-how quickly does it progress, are you seeing any evidence of insects any where on the plants, particularly under the leaves....

Hi Ed,
I know exactly what you're talking about! (Glad to hear it hasn't spread to Lincoln county!).
Oregon Department of Agriculture investigated the issue a year or two ago. damage is caused by an insect called the greenhouse thrips (Heliothrips haemorrhoidalis). As the common name suggests, this pest is predominantly associated with greenhouses in temperate climates as it is supposedly not cold hardy. It can be a significant pest in warmer climates, such as California in the avocado areas and in Florida. It predominantly attacks shrubs or trees. We've seen it in greenhouses for years but found it in outside samples from Hoyt Arboretum several years ago. About ten years ago, it was causing substantial landscape damage in the Seattle area to viburnum and salal, amongst other shrubs.

And now it's here, and as you have observed, it has caused quite a bit of damage to salal in the area. There's really not much that we can do about it that I know of, except hope it cycles through. Hopefully, this cold winter we just had worked its magic on the thrips and killed a bunch of them off. We'll have to wait and see.


thanks for the response. i looked at a leaf of the affected salal, i used a good microscope, i could not find any thrips. I dont know how small they are, but i should have been able to see them. also the plant takes awhile to completely die off. Like you said hopefully this last winter will help get them under control. thanks again
Ed

My name is Scott Thiemann and I am the Program Assistant for the Master Gardeners in Curry County and we have had this question a number of times this year as well as last, starting with an inquiry from the Port Orford Area. As a result, I took a sample to Jim Labonte at Oregon Dept of Ag and the info given above by Cassie is all we have until now. Regarding not being able to find the 'culprit', it's probably because the damage has been done already and the insects may have moved on...we can only hope that this winter's weather did take a toll on the thrip population! What we will be waiting to see is if the areas affected do come back.