June 27, 2007

Christmas Tree Scouting Report #14 - June 27, 2007

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

This will be the last scouting report for the 2007 season. Thank you for your support and interest in the program. There will be changes to the scouting program beginning next season. The PA Department of Agriculture will no longer support a scout for 1-800-PENN-IPM. More information about a future scouting program follows this report.

Japanese beetles have emerged and were found flying and congregating in high numbers throughout fields in Lancaster County this week. No damage was evident. However, last year adult beetles were seen chewing on the bark of Concolor fir in Lebanon County . Damage to large conifers by Japanese beetles is usually insignificant. Growers that have seedling beds may have to be concerned with the immature grub stage that can pose a threat to the fine roots of seedlings or for those growers digging nursery stock and shipping balled and burlap stock out of a Japanese beetle quarantine zone and into a non-infested area.

Eggs and crawlers of Cryptomeria Scale were still present on Fraser fir in Schuylkill County. Eggs and crawlers are present for six to seven weeks, with peak numbers of crawlers emerging during the first two to three weeks. Eggs of the second generation appear anytime from the last week in July to the first week in August, with crawler emergence beginning by mid to late August. Crawlers emerge over an extended period, making repeat sprays necessary. When there is more then one generation per season control can be difficult because generations tend to overlap and all life stages can be present.

Pests to consider in the coming fall are spruce spider mites. Remember this is a cool season mite and once daytime temperatures resume into the low 80's or cooler, the spruce spider mite becomes active again. To sample for mites tap branches over a white surface and look for tiny red mites with a hand-lens. Control mites with two applications 7-10 days apart unless the label says otherwise.

Eriophyid mites are another cool season mite that do damage on Colorado blue spruce and Norway spruce. Look for bronze color needles on Norway spruce and a bleached out color to the needles on Colorado blue spruce. Not all miticides work for eriophyid mites because of the difference in mite biology. Chemicals that work to control eriophyid mites are Sevin, Dimethoate and oils. Remember oil will remove the blue boom from glaucous trees.

Fall is a good time to spray for overwintering Cooley spruce gall adelgids on both Colorado blue spruce and Douglas fir and the eastern spruce gall adelgids on Norway spruce. These adelgids do not over winter with the protective white waxy covering that they begin to produce in early spring when thy resume development as temperatures begin to warm.

Request for individuals to participate in a spring 2008 Christmas tree pest scouting training program:

The Pennsylvania Department of Agriculture, entomology division will no longer be offering a scouting service to the Christmas tree industry in Pennsylvania.  The duties of the department are shifting toward invasive and exotic pest surveys. If a scouting program is to continue, the Christmas tree growers will have to support the program themselves. To do this, PDA entomologist Sandy Gardosik, has offered to conduct a free training program during the spring season of 2008 to any employee of a Christmas tree operation (owner, manager or other staff) who will be willing to make the commitment to the program. Growers will be asked to scout on their own farm for pest and diseases that would have an economic impact on their business. Growers will also be asked to report their findings on a weekly basis by phone or email to a central data center. The data will then be compiled to generate a weekly newsletter that will be distributed electronically to interested growers. 

Growers who are interested in the 2008 training program and are willing to help support the program on a weekly basis throughout the growing season are asked to email Sandy Gardosik at Please include name of business, contact person, phone number and address, including county where farm is located.