The following is information on scales where crawlers are now active in the landscape. This is a good time for control measures.
Minute Cypress Scale
Examine Leyland cypress in June for yellowing, dieback and presence of white scale covers that look like snow flecking on the needles. Crawlers just started emerging on June 8.
Control: Since the crawlers are just emerging 0.5 % horticultural oil and Distance or Talus would be good materials to apply.
Japanese Maple Scale
We have been monitoring the Japanese maple scale for the last couple of weeks since so many people are interested in when the crawlers start showing up. Crawlers have emerged.
Control: In the next week or so you might want to apply the IGR Distance. Many growers are mixing Distance with 0.5 - 1.0 % horticultural oil.
We examined a sample of arborvitae that had Fletcher scale and found that the crawlers have emerged.
Control: You can use Distance when crawlers emerge. Another option is soil applications of imidacloprid.
Information from the June 12, 2009 edition of the TPM/IPM Weekly Report for Arborists, Landscape Managers & Nursery Managers from the University of Maryland Cooperative Extension.