During pruning this winter, there have been some reports of Japanese maple scale on apple trees. I have posted a photo of once such instance below, submitted in January by Extension agent, Tim Ohlwiler. Japanese scale has a broad host range and two generations per year in our area, and overwinters as immature 2nd instars. As with other scales, its management begins with an application of dormant oil (2-3%) prior to bud break in the spring, when temperatures are above about 55 F for 4 to 5 days. First generation crawlers should be targeted between mid-May and early June using 2% horticultural oil alone or at 0.5 – 1% in combination with Esteem or Centaur. Second generation crawlers should be targeted in early August, using the same products as for 1st generation. Researchers at the University of Maryland published a very informative fact sheet about Japanese scale biology and management that can be found at the following link.
