Pest Activity -- May 8, 2000

Pest Activity > Pest Activity Archives > May 8, 2000

Welcome to the Woody Ornamental Pest Scouting Report for Western Pennsylvania for May 8, 2000, brought to you by Penn State Cooperative Extension. This tape will be updated weekly with growing degree day counts and insect activity through the end of June. If you would like an email copy of this report, send your request to mcm2@psu.edu.

As of May 3, the following growing degree days using a base temperature of 50 degrees have accumulated:

Fox Chapel	214
Butler	146
Uniontown	262
New Stanton	214

Pine Needle Scale crawlers were on the move in the city of Pittsburgh and in Westmoreland county this past week, while crawlers in Sewickley were still beneath the protective scale cover. Now is the time to check the needles of Mugo, Scotch, Red and Austrian pines for tiny red crawlers are migrating from beneath the scale covering to a new site. Two applications of a pesticide are recommended if you are trying to control a heavy infestation of this scale insect.

Birch Leafminer larvae were observed in Sewickley this past week with the irregularly shaped mines measuring 3/8" across. There are several generations per year of this leafmining sawfly, but only the first generation warrants control. If mines are present, a systemic insecticide should be used to kill the developing larvae. Please consult the current Penn State Pest Control Suggestion Guide for more detailed information.

European Pine Sawfly in Westmoreland county measured 5/8" long and have begun devouring entire needles leaving short stubs on Scotch pines. Control measures at this time include physical removal or a spot treatment with a pesticide labeled for control.

Eastern Tent Caterpillar larvae are active in all counties in southwest Pennsylvania with caterpillars observed in Allegheny county measuring 3/4" long. If you plan to use the insecticide B.T. for this pest, remember that the best results occur when the larvae are under one inch long. If using a contact insecticide, be sure to apply during the day when the caterpillars are feeding outside of the tents.

Spruce Spider Mites remain active on spruce, junipers, arborvitae and other conifers. To check for the presence of this mite shake the branch of the spruce tree while holding a white piece of paper underneath to catch the mites. If you have a mite infestation, you will see small reddish dots moving on the paper.

Eriophyid mites continue to be active on hemlocks in Westmoreland county. Registered insecticides applied according to label directions should be used at this time if mites are present.

To clear up some confusion that may have been created by descriptions of mite damage on hemlocks in earlier reports, the damage from Spruce Spider Mites is characterized by a whitish appearance of the foliage. Closer examination will reveal speckling on the needles where the leaf color transitions from white to green. On the other hand. Eriophyid mite damage is characterized by tiny, yellowish streaks in the needles.

The next tape update will be on Friday, May 12th.