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April 4, 2003

Christmas Tree Scouting Report -
Number 2

Welcome to the Christmas Tree scouting report ending the week of April 4, 2003. A new report detailing insect, mite and disease situations from the current week will be prepared every Friday. The next report will be out after 4:00 pm Friday April 11th. To receive a FAX copy of this report, please call 814 865-1636.

You can contribute to these reports by calling Sandy Gardosik at 717 772-0521 or Rayanne Lehman at 717 772-5229. Please leave a message with details such as pest name and stage, type of host tree, county location, date and what was happening. Your name and telephone number would be useful if we have any questions. For those of you receiving email reports, you can also send scouting observations by email. This year's fluctuating spring temperatures are giving growers a chance to stay abreast of the pests. Are you?

Forsythia is blooming in Chester, Dauphin, Lebanon and Perry counties this week. This is a good reminder of some early pests to be evaluating at your own farm. There is still time to spray for the Cooley and eastern spruce gall adelgids, if you haven't done so already. In Schuylkill and York counties the overwintering stem mothers are still exposed enough to get good control. Once theses stem mothers are completely covered in wax, controls will not be effective.

Balsam twig aphid is beginning to hatch on true firs in York County this week. There were overwintering eggs found in Berks and Schuylkill counties but no hatch was observed. I suspect by next week we will see hatched nymphs on the undersides of needles in all of the lower counties. Eggs are less than 1/16 inch in size, black and covered with fine slivers of white wax. They are difficult to see without magnification. Once hatched the yellow to gray/green nymphs are easier to see with the aid of a hand lens. Usually, actively feeding aphids will have a small ball of honeydew on their back end. The honeydew is a waste product from feeding.

As bud break begins these nymphs mature and rapidly produce offspring. The aphids feeding on the new expanding needles cause needle distortion and curling. The best time to spray for this pest is closer to bud break when all over winter eggs have hatched but before new growth begins. If you know you have this problem you may want to consider spraying for this pest in the next few weeks. We will continue to monitor for this pest at various location.

At a site in York County many Pales weevils were found around fresh stumps. There has been heavy feeding damage on white pine, scotch, Douglas and true fir at this location. These weevils will feed on the bark of many conifer species but prefer Scotch pine stumps for breeding. A registered stump spray at this time of year will bring this pest under control. If infestation is heavy and many young trees in the field have been damaged by Pales feeding in the past, a pre-plant dip to any seedlings being planted this year may be a good idea.

The white pine weevils are active in Schuylkill County this week. Many Christmas tree growers plant other landscape plants and those who also grow Serbian spruce know this weevil can do considerable damage to the terminal. Serbian spruce and eastern white pine are both good species for monitoring white pine weevil. In most locations, it is too late to install detection traps.

Eriophyid mites are continuing to hatch on blue spruce in Berks, Chester, Columbia and Schuylkill counties. These mites were also on Norway spruce in Chester Co. Now is the time to spray before numbers build and damage becomes noticeable. Not many registered insecticides are labeled for this pest so be sure to check the label on your miticide for eriophyid or rust mites. Apply a second spray to control mites that were in the eggs stage at the time of first spray.

Many of you are reminded of the late frost we had last year because of all those dead tips and naked branches visible on the tree. Occasionally, buds will proliferate on freeze-damaged tips and result in a type of witch's broom. Tip needles that are distorted and much smaller than normal may also be a result of heavy frost damage.

Pine bark adelgid was found covered with white cottony looking wax on buds and bark of eastern white pines in Schuylkill County this week but no eggs were present. These sucking insects feed only on the bark - not the needles. Heavy populations may weaken and degrade trees but light populations do not usually require control. The introduced multicolored Asian ladybeetle is an effective predator on these adelgids.

Spruce spider mite eggs are heavy on some host trees but no hatch has been observed. Look for this important pest of conifers, especially true firs, to become active when Growing Degree Days are closer to 100, base 50°F. Scouting now for the red overwintering eggs can yield results later when monitoring the hatch is important.

If you are interested in tracking pests by Growing Degree Days, you can obtain reports for your local area at http://www.nass.usda.gov/pa/ . Click on Crop Weather along the top margin and select a site near your farm.

The next report will be available on Friday, April 11th.