Pest Activity -- May 12, 2000

Pest Activity > Pest Activity Archives > May 12, 2000

Welcome to the Woody Ornamental Pest Scouting Report for Western Pennsylvania for May 12, 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 10, the following growing degree days using a base temperature of 50 degrees:

Fox Chapel	358
Butler	227
Uniontown	408
New Stanton	333

Four-lined Plantbug damage was observed on numerous perennials this past week in Allegheny county. Their feeding on the upper leaves of many herbaceous perennials results in numerous 1/16" brown spots.

Feeding punctures caused by the Native Holly Leafminer were observed in Sewickley this past week. The adult females will soon be laying eggs in the new growth so control applications should be applied at this time.

Pine Needle Scale crawlers continue to emerge from beneath the scale covering in the city of Pittsburgh,Westmoreland county and in Sewickley. In Sewickley, a few crawlers were settling and beginning to feed. Now is the time to check the needles of Mugo, Scotch, Red and Austrian pines, the preferred host plants for this pest. Two applications of a pesticide are recommended if you are trying to control a heavy infestation of this scale insect.

Birch Leafminer larvae observed in Sewickley this past week were 1/2" long and some leaves were almost entirely "mined out." 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.

European Pine Sawfly in Westmoreland county are just under one inch in length and have begun devouring entire needles leaving short stubs on Scotch and Mugho pines. Control measures at this time include physical removal or a spot treatment with a pesticide labeled for control.

Many of the Eastern Tent Caterpillar larvae observed in Allegheny County are over one inch in length at this time. 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.

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.

The candles on Austrian and Mugho pines are still expanding so if you are spraying to control Diplodia Tip Blight, fungicide applications should be applied on a 10-14 day interval until the needles reach full size.

The next update will be on Friday, May 19th