Euonymus Scale Begins Overlapping Generations
Originally posted on ecoIPM.org
It seems like everything is labeled ‘next generation’ or ‘second generation’ to imply a better, more sophisticated version. The second generation of euonymus scale is about the same as the first except a bit harder to manage. This is because the first generation is usually synchronized so all the crawlers on a plant emerge within a couple weeks or even a couple days. However, by the second and third generations they fall out of sync as some develop faster than others. Thus, for the rest of the summer you will find all stages of the scale at the same time; the soft vulnerable crawlers will be mixed with tough armored adults.
A good way to manage euonymus scale is to remove euonymus from your landscape. If you have the plant you are guaranteed to have the scale. If you are a grower or just love the shiny evergreen leaves you can treat euonymus scale with insect growth regulators or some of the neonicotinoids including dinotefuran, thiamethoxam, or acetimiprid. (Remember imidacloprid is NOT effective for armored scales and in some cases makes them worse.)
Euonymus scale infests the leaves and branches of euonymus. It is noticeable by the yellow chlorotic spots on the tops of leaves where scales are feeding below. You will also see white fuzz which are the unarmored male scales. The females are gray and oyster shell shaped.