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June 8, 2005

Christmas Tree Scouting Report -
Number 11

Welcome to the Christmas Tree Scouting Report for the week ending May 11, 2005. The next report will be available after 5 PM on Wednesday, May 18. To receive a FAX of this week’s message, please call (814) 865-1636. If you have pest activity to report, or would like to receive this report by e-mail, please leave a message at 717 772-0521 or e-mail sgardosik@state.pa.us and your name will be added to the distribution list.

Rhabdocline needlecast is still infectious in Dauphin, Lancaster and Perry counties. If you applied your last spray about two weeks ago you will want to consider applying another. Those of you who just completed your third spray a few days ago will need to examine the undersides of infectious needles before you're scheduled to spray again. However, those growers that are also spraying for Swiss needlecast will definitely want to apply a fourth fungal spray because of the longer sporulation period.

Spruce needle rust is still infectious on Colorado blue spruce in Bucks and Schuylkill counties and growers should follow the same schedule as for Rhabdocline.

Eggs of cryptomeria scale were more numerous this week in Dauphin, Lancaster and York counties. Now would be a good time to scout for eggs by taking a branch you know has scale and tapping it on a white surface to dislodge very tiny lemon yellow eggs. A 10x or stronger hand-lens will add in viewing eggs. Damage from this scale causes spotty chlorosis on the tops of needles and when examined from underneath adult scale can be seen. Adult scales are about 1 to 1.5 mm wide with a tan armor cover with a yellow center - looks like a sunny-side-up egg. I expect to see the first crawlers within the next week.

Bagworm larvae were still emerging from the over wintering bags in Dauphin and Lancaster counties. Best control is achieved when the larvae have emerged from the bags and are actively feeding but still small.

Damage from the white pine weevil is noticeable in the terminals of white pine, and Serbian spruce in Schuylkill County and in Norway spruce and white pine in Perry County. Look for terminals with light brown, stunted or drooping new growth. If the white pine weevil is the causes of these symptoms the bark will be soft and easy to peel.  Removing the bark will reveal a white larva with a tan head. Now is the time to scout for this damage and cut out any infested terminals before more then one year's damage is lost. Make sure your cut is below all infested wood and all cuttings are removed from the field and burned.

The balsam twig aphid was found feeding in the new growth on Concolor and Fraser fir in Adams, Franklin and York counties. Feeding by these aphids cause distortion of the new growth on Fraser fir.  On Concolor very little damage is caused by aphid feeding. The winged aphid stage is developing which means the life cycle of this aphid is coming to an end and the majority of the damage is done. Fortunately the needles will continue to elongate and outgrow 50% of the damage by late summer. Now is not the time to spray because the damage is already done and natural predators such as lacewings, syrphid flies and ladybird beetles are feeding on the aphids. Make note as to where the damage occurred so next year you can apply your insecticide before bud break.

Eggs of striped pine scale were found underneath the female's body on Scotch pine in Lancaster County. This is a soft scale that is best controlled when crawlers start to hatch. I suspect crawlers within the next week. At a site in Perry County this same scale was being controlled naturally by a lady bird beetle known as Hyperaspis stigmata. The larva of this ladybird beetle has a white powdery covering that is sometimes mistaken as a mealy bug or another bad bug. Hyperaspis larvae are very effective in controlling the striped pine scale and can easily crawl under the scale covering to consume the soft-bodied scale insects and eggs.

The next report will be available on Wednesday the 15th after 5:00pm.