June 14, 2006

Christmas Tree Scouting Report No. 14 - June 14, 2006

Weekly newsletter compiled by Sandy Gardosik, PA Department of Agriculture.

Since last week's report, many more eggs of the Cryptomeria scale were found beneath female scale's covers. Crawler activity is most active on Fraser fir in Berks and York counties. Crawlers were also found on concolor fir in York County. Crawlers can be found moving over the needles in search of suitable feeding sites, or have settled and begun to feed and produce their protective covers. In Dauphin, Lancaster, Lebanon and Schuylkill counties eggs are hatching underneath the adult female scale's covers, and only a very few crawlers can be found out on the needles of Canaan and Fraser fir. Once crawlers are detected on the needles, a spray program should begin within the next couple of days, since crawlers and early settled nymphs are the stages most susceptible to chemical controls. Since eggs hatch over several weeks, the best control can be achieved by three spray applications spaced 7 to 10 days apart.

Crawlers of the striped pine scale are very active this week on Scotch pine in Dauphin County. This is a soft scale, which means it does not produce a protective armor or covering, as does Cryptomeria scale. To control this scale, growers can wait until all crawlers have emerged from beneath the adult female before applying a registered insecticide.

Spruce spider mites are beginning to move out onto the new growth of Fraser and Canaan Fir in Schuylkill County. This year's cool spring temperatures have caused mite populations to explode. I suggest going back and scouting those fields you sprayed earlier this spring, or those you decided not to spray because they contained small trees, and check for any rebound of mite build up.

Balsam twig aphid overwintering eggs were found on branches of Fraser and Canaan fir in Schuylkill County. This indicates this pest's life cycle for the year is coming to an end. Take note as to what fields were damaged by the Balsam twig aphid so controls can be applied before bud break next year.

The majority of young bagworm larvae have emerged from last year's overwinter bags and controls should be applied before larvae begin to do noticeable damage.

"Chip cocoons" were found in the terminal leader of a white pine in Lebanon County that was showing the "Shepherd's crook" symptom. The "chip cocoon" indicates the larva of the white pine weevil is mature and beginning to prepare for pupation. Keep an eye out for wilting terminal leaders when shearing white pines and prune out any damage and remove it from the field. Keep in mind all species of Christmas trees are hosts to the white pine weevil.

If you have any pest information to report, please email Sandy Gardosik at or call (717) 772-0521 and give pest, host plant and county where observation was made and I will include this information in the next report.