Pest Activity -- April 28, 2000

Pest Activity > Pest Activity Archives > April 28, 2000

Welcome to the Woody Ornamental Pest Scouting Report for Western Pennsylvania for April 28, 2000, brought to you by Penn State Cooperative Extension. This page 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 April 19, the following growing degree days using a base temperature of 50 degrees have accumulated:

Fox Chapel	174
Butler	121
Uniontown	224
New Stanton	172

Pine Needle Scale crawlers were observed in the city of Pittsburgh and in Westmoreland county this past week. The tiny red crawlers are migrating from beneath the scale covering to a new site on the needles of Mugo, Scotch, Red and Austrian pines. Two applications of a pesticide are recommended if you are trying to control a heavy infestation of this scale insect.

Birch Leafminer adults were observed in Sewickley this past week. While no mines were present, females were laying eggs. There are several generations per year of this leafmining sawfly, but only the first generation warrants control. Insecticide treatments should be applied when the adults are active and before the mines or tunnels are present in the leaves. 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.

White Pine Weevils eggs but no larvae were observed in the leaders of White Pines in Westmoreland County this week. Any pesticide applications at this time will only prevent further egg laying but will not affect the eggs already deposited by the adult females.

Boxwood Psyllid nymphs were observed this past week in the City of Pittsburgh. The feeding activity of this pest causes the cupping of the terminal leaves on boxwoods and treatment should be applied now before the nymphs become adults.

Preventative fungicide sprays for Diplodia Tip Blight on two and three needled pines should begin during candle elongation and repeated on a 10-14 day interval until the needles reach full size.

Pine Spittlebug nymphs were observed this past week on white and Scotch pines in Westmoreland County. Unless heavy infestations occur, this pest rarely warrants the use of insecticides.

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.

European Pine Sawfly feeding on the terminal growth of Scotch, Japanese Red and Mugho Pines measured 1/2" long. Control measures at this time include physical removal or a spot treatment with a pesticide labeled for control of this pest.

Cooley Spruce Gall Adelgid adults in Westmoreland county are completely covered with white waxy filaments thus closing the spring window of opportunity for control of this pest. Any pesticide control measures should be delayed until September.

Eriophyid mites continue to be active on hemlocks in Westmoreland and Beaver counties. Registered insecticides applied according to label directions should be used at this time.

Crabapples that are highly susceptible to apple scab can be sprayed at this time. Recent research indicates that a combination of the fungicides Banner and Daconil provides very good control of apple scab when applying either 3 sprays at two week intervals or 2 sprays at 3 week intervals. Initial sprays for apple scab on crabapples should be applied now. If you are considering a crabapple for a new installation, please call the extension office at 412-473-2540 for a list of disease resistant crabapples or we can be reached via e-mail at AlleghenyExt@psu.edu

The next page update will be on Friday, May 5th.