April 6, 2005
Christmas Tree Scouting Report -
Welcome to the Christmas Tree Scouting Report for the week ending Wednesday April 6, 2005. The next report will be available after 5 PM on Friday April 15 th. To receive a FAX of this week’s message, please call (814) 865-1636. If you would like to receive this report via email, please send a request to firstname.lastname@example.org and you will be added to the distribution list. To contribute observations to this report, please email to the address above or call 717 772-0521
The white pine weevil began to emerge after the warm days last week. Since Friday there has been weevil activity in Berks, Carbon, Chester, Lebanon, Perry, Schuylkill, and York Counties. Trap counts have been as high as 18 weevils per trap. It appears that the weevils go to the baited traps soon after they begin to emerge from their over wintering site beneath previous years damaged trees. There has been little feeding activity found on the terminal leaders in fields set with traps or fields where weevils were found on terminals. However, with more warm days in the sixties and seventies, growers can expect to find the small pinhole size damage to the terminals caused by weevil feeding. Weevils will be emerging for the next couple of weeks and feeding for a short time before females lay their eggs. Chemical application should be made to the top 1/3 of trees once weevils begin to emerge so the material is there for the weevils to ingest. A second application may be needed. At our monitoring site in Perry County, traps baited with denatured alcohol trapped as many weevils as our traps baited with 95% ethyl alcohol. The trap baited with 70% isopropyl alcohol (rubbing) had a significantly lower weevil count. What does this all mean? Well, you can now go to your local hardware store and purchase denatured alcohol along with your turpentine instead of purchasing a liquor license or driving to Maryland for grain alcohol.
Spruce spider mite eggs were found on Canaan and/or Fraser fir in Carbon, Chester, Dauphin, Lancaster, Lebanon, and York counties. Egg hatch will not be for a few more weeks. To scout for these eggs, start by looking for damaged needles that have a washed out yellow to tan look at the base of the needle surface. With your hand lens look for small, round, red eggs on the bottom of twigs, in between the needles and/or at the base of needles. An early dormant oil can be used at this time to control the over wintering eggs. Make sure you get good coverage and apply when temperatures are above 50 degrees with no chance of freezing before oil dries. Remember, if dormant oil is used on Colorado Blues, the blue bloom will be removed and will not return till the new growth comes out and covers the old growth up.
Those of you who scout your trees using a hand lens may notice small black spots randomly scattered on the top and bottom of needles and bark on Douglas fir and spruce. This is a fungus known as “fly speck” and causes no significant damage to the tree. Since this fungus just sits on the surface it can easily be rubbed off.
There is still time to spray for Cooley spruce gall adelgids on Douglas fir and Colorado spruce and eastern spruce gall adelgids on Norway. However, once forsythia is in full bloom the window for control is over. If the warm weather continues it will not be long until the nymphs are covered with white wax and not susceptible to chemical control.
Growers that plan on trapping for the Douglas fir needle midge should start placing traps under Douglas fir trees that had damage last year. Traps will be going up at our monitoring sites later this week and next. (You can find instructions for constructing the Douglas fir needle midge traps by clicking on DFNM traps). This midge is specific to Douglas fir and has been doing damage to the needles in the southeast counties the last couple years. Damage in some areas has been serious enough to warrant control.
More on the DFNM and other pests of concern in the next report that will be available FRIDAY the 15th after 5:00 PM.