Share

March 18, 2002

Christmas Tree
Preseason Scouting Report

Our ninth season for the Christmas Tree Scouting Report will officially begin on March 29, 2002. But, a record-breaking warm winter and early spring have caused insect and mite activity to be several weeks ahead of schedule. This pre-season report is to give you a "heads-up" for several important pests.

White pine weevils are active and have been attracted to detection traps in Perry County. This week, adult weevils were present on terminals of eastern white pine in Snyder County. The weevils are feeding and characteristic sap droplets are present on the terminals but no eggs were present in the terminals examined. Growers wishing to apply registered insecticides for control of this serious pest of pine, spruce and Douglas fir should make their applications to the top one-third of the trees as soon as possible. Because of the very early spring activity, it may be necessary to make several applications in 2002. We will be monitoring for this pest and will keep you advised.

In the Harrisburg area, and locations south and east of the capital, forsythia has started to bloom. This marks the spring control period for Cooley spruce adelgids on Colorado spruce and Douglas fir and also for eastern spruce gall adelgids on Norway spruce. The pest stages on spruce are probably of greater concern than those on Douglas fir, since the spruce growth is severely altered by formation of galls. Spring control of all of the stages can be achieved now, before the overwintering nymphs molt into stem mothers and cover themselves with wax.

Extensive damage from feeding of Pales weevil adults on tender bark of healthy eastern white pine was noted in Snyder County. Growers wishing to control Pales weevil should be making an application of an approved insecticide to stumps of trees cut in 2001. Trees cut before spring 2001 are not acceptable as breeding sites and do not need to be treated. All currently registered insecticides for stump treatments of Pales weevil use water as a carrier; diesel fuel and motor oil are no longer recommended.

In Perry County, pine bark adelgids have matured and the stem mothers are depositing clutches of eggs under white wax. Farther north in Snyder County, no eggs have been deposited.

Spruce rust mite, and eriophyid mite, is active in Columbia and Snyder counties. In Perry and Snyder, white pine eriophyids are also hatching from overwintering eggs. No spruce spider mite eggs have hatched at any location.

This is a great time of year to be scouting for several diseases, including rhabdocline needlecast on Douglas fir. The red-brown blotches on last year's needles are characteristic of this serious disease. Controls will not be applied until closer to budbreak.

We look forward to another year working with Christmas tree growers in production of this scouting report. To make the report usable for a wider geographical area, we need input from growers. We are unable to regularly visit locations farther than 2 hours drive from Harrisburg. If you see some pest activity and would be willing to share you information, please email it to me at rlehman@state.pa.us or call 717 772-5229. Tell me the pest, stage of pest, host, and location and I'll be sure to add it to our report.

Growers wishing to automatically receive an email copy of this report each Friday should send an email to me at rlehman@state.pa.us and I will add you to the distribution list.

The first regular report will be available after 4 pm on Friday, March 29.