August 13, 2008

Update on the Second Generation of Cryptomeria Scale

Eggs of Cryptomeria scale have been found on Canaan and Fraser firs in both Schuylkill and York Counties this week.  In Schuylkill County, the eggs were first seen on Wednesday, July 31st as 1730 growing degree days, so these eggs should begin hatching very soon.  They could be out before the end of this week.  Growers who missed the control period for the first generation in June or who were not happy with the level of control they achieved from their sprays in June should be getting ready to spray for this second generation of scales.  The eggs, which are yellow and capsule shaped, are found underneath the white, waxy coating of the adult female.  When they hatch, the nymphs or crawlers will move out from under the adult scale coating.  The crawlers will appear as flat, yellow discs on the underside of the needle.  They will be visible with a 16x hand lens.  The first spray should be applied when these nymphs or crawlers are seen on the undersides of the needles.  It is important to apply the pesticide before the crawlers begin to settle and form their own coverings, which will appear as a white ring around the yellow disc.  Growers should be scouting their trees to find exactly when the crawlers are emerging.  Again, the important tool to use for this is a hand lens.  

Thanks to Jim Fogarty of Halabura Tree Farm in Schuylkill County and Cathy Thomas of the PA Department of Ag for supplying scouting information.