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June 9, 2000

Christmas Tree Scouting Report

Welcome to the Christmas Tree Scouting Report for the week ending June 9. The next report will be available after 4 PM on Friday June 16.  To receive a FAX of this week’s message, please call (814) 865-1636. If you have pest activity at your location to report, or would like to receive email reports, please leave a message at 717 772-5229

This is the week of crawler emergence in central Pennsylvania.  Crawlers of the armored scale pest, known as Cryptomeria scale, have started to emerge in Chester County. Thanks to the grower who report this eastern record. In the Harrisburg area, our scouts found crawlers in Berks, Lebanon, and York counties, but very few had actually started to emerge from under the covering of the female scale. At other sites in Berks County, hatch had not started. Look for the bright yellow, flattened crawlers moving about on the needles and bark. If you shake an infested branch over a dark object, the light colored crawlers are easier to detect. By prying open a few female scale coverings with the point of a straight pin, the yellow eggs can also be found.

This is the perfect time to apply a registered insecticide to control this troublesome pest. Since the scale insects and their mobile crawlers are on the undersides of needles, applicators must take special care to obtain complete coverage. A second application, and perhaps even a third, is required to gain control of this pest. Repeat applications must be made every 7 to 10 days until no crawlers can be found. During the last two years, cryptomeria scale underwent a second generation at our study sites and we expect that to happen in 2000. The second generation usually occurs in mid-late July.

Crawlers of striped pine scale are also active this week in Adams and York Counties. This scale was previously confused with a related species, the pine tortoise scale. Both have hemispherical bodies that resemble miniature army helmets affixed to the bark of branches. In most infestations, dense growth of black sooty mold also accompanies the scale. This is because soft scales secrete significant amounts of honeydew, which is highly attractive to ants and bees.

If you have had a problem with either pine tortoise scale or striped pine scale, you should be checking for the light tan crawlers. They are easy to see as they move about over the dark brown females and bark coated with sooty mold. The crawlers that settle on the needles are those that will become the male scales while those that settle on the bark are the females. There is a single generation of this scale in Pennsylvania.

In preparation for shearing, growers should be aware of the bees and wasps that may be in their trees. Many of these insects are beneficial, until workers get stung repeatedly. Preventing infestations of insects that produce honeydew, such as aphids or striped pine scale, can influence the number of stinging insect nests in the plantation. Applications of any carbaryl product will also have an effect since this material is very deadly to bees and wasps. If nests are found, some over-the-counter wasp and hornet spray can be used to knock down the guard bees before the branch containing the main nest is cut out. The bag containing the nest can be burned to kill the bees. For inground nests, household ammonia can be dumped into to the opening, if it can be found. The best time to control bees and wasps is in the evening, after sundown. Cooler nights are preferred over warm nights. Protect yourself with long sleeved shirt and pants and do not use a flashlight without first covering the lens with red cellophane.

The next report will be available after 4 PM on June 19.