Scale infestation on my Laurel plants

Asked June 14, 2020, 8:17 PM EDT

Is is still advisable not in late June to treat my skip and cherry laurels with horticultural Oil to deal with scale? Reading in some articles that it is recommended to treat in March/April but O’m concerned now having not treated my plants this year and noticing scale. if you recommend The oil, what exactly is the best to use and way to treat? Thanks Michael Stuehler

Baltimore County Maryland

1 Response

Here is our blog on cherry laurel and white prunicola scale.
Crawlers emerge in the spring. Crawler periods vary from year to year depending on temperatures. For this species, new generations may be out in May, mid-July to mid-August, and September. Check for the crawlers and then spray if need be. It is possible you may be able to prune out some branches selectively, if the infestation is small.

The tiny juvenile crawlers are salmon-colored. You can place a simple trap to detect their activity; wrap a piece of double-sided tape around a few branches. When you see crawlers stuck to the tape, that is the ideal time to apply horticultural oil.
Follow label directions and do not spray in high temperatures.

Check them periodically for leaf yellowing and white spots on lower branches. Scales are easier to manage if you catch them early.

Also, fertilized female scales overwinter on the bark of the branches, so another step in management is to apply a dormant rate of horticultural oil during the dormant season (when deciduous plants have lost their leaves). You can first use a soft-bristled brush to scrub off the scale patches gently. Then apply the horticultural oil.