Pest Activity -- April 19, 2002

Pest Activity > Pest Activity Archives > April 19, 2002

Welcome to the Woody Ornamental Pest Scouting Report for Western Pennsylvania for April 19, 2002, brought to you by Penn State Cooperative Extension.This message 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 17, the following growing degree days with a base temperature of 50 degrees have accumulated:

Uniontown	195	Franklin	139
New Stanton	172	Meadville	116
Pittsburgh	170	Erie	103
Wexford	149	Fairview	92
Prospect	114	Harbor Creek	86
Mercer	101

Baldcypress Rust Mites were active in Westmoreland County last week.

The young nymphs of both Honeylocust Plant Bugs and Honeylocust Spider Mite were also active in Westmoreland County Last week.

Birch Leafminers adults were observed in the City of Pittsburgh and the Sewickley area this week and will be laying eggs in the expanding leaves over the next couple of weeks.

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

Pine Spittlebug nymphs were observed this past week on white and Scotch pines in Westmoreland County. This pest rarely warrants the use of insecticides for control.

Southern Red Mites have hatched and young nymphs were observed on Japanese Hollies in Westmoreland County last week.

Eastern Tent Caterpillar hatched out this past week in Westmoreland and Allegheny counties. The tents are approaching 1-2 inches in length and the larvae are in early instars.

Adult Inkberry leafminers, a key pest of Ilex glabra or inkberry holly were active again this week in western Pennsylvania. Control sprays should be applied when the adult flies are active to prevent egg laying. The adult is a tiny 1/8" long blackish colored fly and can be seen laying eggs in last years foliage on inkberry holly. This pest also has a second generation that occurs from mid-August to mid September.

European Pine Sawfly eggs are hatching in Allegheny and Westmoreland counties and the 1/4 inch long larvae can be found feeding on last year's terminal growth. Their preferred host plants are Scotch, Japanese Red and Mugho Pines. At this time the larvae are confined to a localized area and a spot treatment or physical removal will provide control.

Spruce Rust Mites and Hemlock Rust Mites remain active on Spruce and Hemlocks in Western Pennsylvania at this time.

The majority of the Cooley Spruce Gall Adelgid nymphs scouted in Westmoreland County were covered with white waxy strands, closing the window of opportunity for control sprays.

The next scouting report will be on Friday, April 26th.

Use of Imidacloprid in the Landscape

Here are some thoughts on the use of Imidacloprid in the landscape from David J. Shetlar,
Associate Professor of Urban Landscape Entomology at The Ohio State University from his P.E.S.T. Newsletter for April 22, 2002:

Imidacloprid (=Merit, Marathon, and Bayer Advanced Garden Tree & Shrub Insect Control) is being recommended for a variety of landscape pests and I wanted to provide information on what is, and is not known!

First, Drs. Dan Herms and Dave Nielsen have been performing evaluations of imidachloprid products for years for control of a variety of critters, as have other ornamentals entomologists across the country.

Scale Control
At present, only soft scales appear to be controlled with imidachloprid applications. This would include lecanium, calico, magnolia scales and the cottony maple scale. While there is some evidence that imidachloprid may provide some control of adult scales, the best targets are likely settled crawlers and second instars. Therefore, applications on spring egg laying forms (everything except magnolia and tuliptree scales) should be most effective if applied 30 to 60 days prior to egg hatch which occurs in mid- to late June. Therefore, applications in April and May would meet this target time. Applications have also been effective when applied in October into December.

Sawflies
Dan showed me a row of pine trees treated with imidacloprid in October two years ago. By June it was evident which trees had been treated and which ones hadn't. The untreated pines were severely defoliated by the pine sawflies. branch defoliation.

Japanese Beetle Adult Control
Apparently, telemarketers have been busy trying to sell Ohio residents on imidacloprid injections to protect their trees from Japanese beetle adult feeding. The companies selling this service are generally using the ArborSystems Pointer and Wedgle injector. Pointer contains imidacloprid and the Wedgle is a hypodermic-needle-like apparatus. In evaluations, plants containing imidacloprid kill Japanese beetle adults, but the adults have to feed before they die. In other words, the plants look much better than if they weren't protected, but damage IS evident. Unfortunately, some of the telemarketers are suggesting that no damage will occur.

Injection into the tree trunk is also not essential for getting imidacloprid into the plant. Soil drenching and soil injections will accomplish the same task. However, allow about 40 days for the pesticide to move from the roots to the leaves. Once in the leaves, imidacloprid will remain at active levels for two to three months.