Kind gardeners,

I just pulled a couple of leaves for a better look and have to admit my
initial description was a bit off. The topside of the leaves has
yellow-white very fine speckling or mottling, and there is also dark
mottling on top and bottom that looks like physiological leaf spot. There is
no notching (root weevil) but close inspection reveals a couple of tiny
light-colored insects on the underside (maybe one or two on each leaf), too
small to make out details using a 10X loupe. The pictures of rhodie lace bug
damage look quite a bit like what I'm trying to describe, along with the
physiological leaf spot. It doesn't look to me like powdery mildew or gray
blight, whitefly, rust or virus; definitely not chlorosis.

There has been no lime or wood ash added to the soil. I mulch with leaves
and compost and added one or two applications of a rhodie food over the
season. A soil test taken early last year returned a pH of 6.2. The sample
was very low in sulfur, very high in iron and phosphorus, high in organic
matter, potassium and zinc. The Comments mention low levels of sulfur may
cause yellowing and lack of vigor but that sulfates may have leached below
the sampling depth. Boron level was 0.4 and Comments suggest aiming for
levels above 0.5 ppm to avoid deficiency.

What would be the best way to add sulfur and boron? One of the posts
suggested treatment for lace bug, so I'll copy that and give it a try. Hope
I haven't lost them yet! Any other thoughts would be appreciated.

Thanks all.

Karen
Portland, OR