August 4, 2006
Christmas Tree Scouting Report - August 4, 2006
Pest update on the 2nd generation of Cryptomeria Scale, compiled by Sandy Gardosik, PA Department of Agriculture.
(The following are observations of cryptomeria scale on Fraser fir.) In York county eggs are just beginning to hatch, but crawlers have not yet emerged from underneath the protective armor coverings of the female scale. In Lancaster county females have been laying eggs for some time, and hatching should begin within the next few days; however, in Lebanon county females are just beginning to lay eggs. In Berks and Dauphin Counties where growers sprayed the first generation of scale, I observed a small number of eggs and immature scales from the late part of the first generation (post-spray) that had not been exposed to the earlier sprays. This will cause the 2nd generation to be delayed, which is another reason it is important to scout your own fields for pest activity (see observation on hemlock below).
I don't normally publish observations from hemlock (Tsuga) since it is not a Christmas tree species, but this observation from the one in my landscape in Dauphin County may be of interest. It has a heavy infestation of cryptomeria scale which was not sprayed during the 1st generation, and it now has a healthy population of scale. When I examined the scales with a hand lens earlier this week, I saw that a few eggs were beginning to hatch, but crawlers had not yet begun to emerge from beneath the female's covering. I'm mentioning this observation for those of you that may grow hemlock for landscape purposes and also to stress the importance of scouting your own fields. The life cycle is further advanced since it was not knocked back with sprays when the first generation crawlers were emerging.