First, as always, you
must properly identify the species of the scale on your
plants. Consult your local
or other plant professional. They should be able to tell
you the life cycle of that species and when the young
(crawlers) are active.
Three approaches may be taken to reduce the number of
scale on the plant:
dormant (horticultural) oil spray may be used
to smother both the adults
and the crawlers. Plants may be sprayed with a highly refined
petroleum product such as Volck oil or Sunspray Ultra Fine oil at the
rate. The temperature must be high enough (usually 40 degrees for several
days) so that the oil will spread evenly over the branches and thus smother
the scale insects.
2. When the crawlers emerge,
they may be controlled by
an oil spray applied at the growing season rate (more dilute) listed on
the product. Or, they may also be treated with other
insecticides labeled for your species of scale.
3. Some systemic insecticides may be labeled for use
on scale. Check the label of the product to be sure
that the species of scale and your species of
plant(s) are listed.