July 26, 2004
Christmas Tree Scouting Report Pest Update
The second generations of pine needle scale crawlers are beginning to hatch on Scotch pine in Perry County and white and Scotch pine in Adams County. Most of the crawlers are still under the white protective covering of the female adult. In Dauphin County adult females were just beginning to lay eggs beneath the protective cover. The eggs and crawlers are both reddish-pink in color. Once the crawlers emerge from beneath the adult cover and begin to settle and start to feed it looks like paprika was sprinkled over the needles.
It is best to wait until all eggs have hatched and crawlers have emerged and begun to feed before applying an insecticide. They will go from the reddish-pink color to more of a yellowish color. This is the hyaline stage and when they are quite vulnerable to insecticides or horticultural oil. It occurs before they start secreting the hard, white, armored covering.
If you only see a few scales on a few trees, don't assume that an insecticide is necessary. You may not need to spray, especially if the trees are at least a year from harvest or the population is low to moderate. There are a lot of natural enemies out there that will attack pine needle scale.
We will begin to scout for the eggs of the second generation of cryptomeria scale this week. Eggs can usually be found the last week in July by flipping over the scale covering with your nail or a pin and exposing the tiny lemon yellow jellybean shaped eggs. You can also tap a branch over a paper plate, which will dislodge the eggs from underneath the covering and with the aid of a hand lens view the yellow eggs. Eggs hatch in about two weeks from the time eggs are laid. We will report on crawler emergence once observed at our monitoring sites.