A Large-Scale Dilemma: 

Drawing shows a shrinking female armored scale laying eggs. Waxy covers of each of the 3-instars are pushed above the other. Crawlers emerge from the female cover through the one-way flap. (Drawing Credit: John Davidson, Univ. of MD)

Undoubtedly many arborists, landscapers, nurserymen, and golf course superintendents would agree that effectively controlling scale insects is one of the more frustrating pest management challenges encountered. Of the half-dozen major families of scale insects common in the urban landscape, the armored scales are the most troublesome. With their protective waxy covering, armored scales are considerably less susceptible to various insecticide spray treatments.

Reddish colored crawlers of Pine Needle Scales emerging out from under female waxy covers. (Photo Credit: Ohio State Coop. Ext.)

Historically, many pesticide spray applicators fail to achieve satisfactory controls because they do not have the time or inclination to apply sprays during the scale crawler emergence periods. To complicate matters, the crawler periods for the various armored scale species are quite variable. Furthermore, the improper timing of long residual pyrethroid insecticides can virtually eliminate important parasitoid bio-control activity and hence, often encourage scale infestations. The intention of this blog is to stress the importance of properly timed treatments to achieve better management of scale insects. This is especially true when attempting to control armored scales.

Despite the complications stated above, fortunately some relatively newer insecticides have given improved abilities for scale controls. These newer materials & the life cycles of 5-armored scale species will be covered in this blog. The scales covered include: 1-Euonymus scale; 2-Cryptomeria scale; 3-Japanese maple scale; 4-White Prunicola scale; & 5-Juniper scale.

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Since there are still over 4-weeks before the official start of summer, the accumulation of growing-degree-days (GDD) will continue to accelerate over the next several weeks. Many of our landscape insect pests will be rapidly emerging and be entering their best control windows before they potentially cause feeding symptoms. This writing contains part 2 of 2 parts of only a handful of the many late spring landscape insect pests that require monitoring. Some could more properly be called mid-spring pests, especially in southern NJ. Those included within part 2 of this blog are: Taxus mealybug; Boxwood leaf miner; Aphid species and Bronze birch borer.

The late spring weeks in the landscape means full plant leaf emergence & many flowers plus increasing insect activity. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

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Since there are still nearly 5-weeks before the official start of summer, the accumulation of growing-degree-days (GDD) will continue to accelerate over the next several weeks. Many of our landscape insect pests will be rapidly emerging and be entering their best control windows before they potentially cause feeding symptoms. This writing contains part 1 of 2 parts of only a handful of the many late spring landscape insect pests that require monitoring. Some could more properly be called mid-spring pests, especially in southern NJ. Those included within part 1 of this blog are: Four-lined plant bug; Douglas-fir needle midge; Pine needle scale; & Elongate hemlock scale.

The late spring weeks in the landscape means full plant leaf emergence & many flowers plus increasing insect activity. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

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As we enter the last week of April, many of our mid-spring landscape insect/mite pests continue to awaken & cause feeding symptoms on our ornamentals. This blog only talks over some of the typical mid-spring pests that plague our landscapes. Those discussed within include: Southern Red Spider Mites; Gypsy Moths; Evergreen Lace Bugs (e.g., rhododendron, azalea, & andromeda lace bugs); Nantucket Pine Tip Moth; Birch Leaf Miner; Hemlock Woolly Adelgid; Plant Leaf Galls (eriophyid mites).

Mid-Spring weeks have arrived & shade trees like this green ash have begun leaf expansion. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

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Throughout much of NJ during this week, the growing degree days (GDD) will be increasing consistently. By the end of the week, many areas will exceed 90 GDD, which means the eastern tent caterpillars will begin to hatch. Not all eggs will hatch at once since a staggered hatching period will potentially increase survival rates if the weather happens to cool again.

The photographs of the eastern tent caterpillar’s life cycle included in this blog were all taken during the spring of 2016 at the same site in Freehold, NJ. They are placed in chronological order covering a time span of 10 weeks from 1^st egg hatch on 3/23/16 to late pupation on 6/2/16. In 2016, central NJ experienced a relatively warm early spring that enabled the speedy first hatching.

Date: 3/23/16 (No hatch). Do you see it? One inch long Tent Cat egg mass overwinters encircling 2-3 year old twigs. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

Date: 3/23/16 (No Hatch). Close-up of the Tent Cat egg mass. It has the appearance & feel of styrofoam. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

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The accumulation of heat units (Growing Degree Days (GDD)) is increasing rapidly across many areas of New Jersey as we soon enter into the early weeks of April. If past histories or present-day monitoring indicate the need for interventions, then the best control windows for an increasing number of insect/mite pests are beginning to occur. The following is an incomplete listing of a handful of some of our early season landscape pests that may need to be scouted & possibly controlled. The insect/mite pests included here are: Hemlock Rust Mites; White Pine Weevils; Native Holly Leafminers; European Pine Sawflies; Honeylocust Spider Mites; White Pine Aphids; and Eastern Spruce Gall Adelgids.

As our landscapes start  to “wake-up” with warming temperatures, the insect & mite pests will begin activity. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

When monitoring indicates controls are warranted, then pesticides can prevent early spring pests from building-up. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

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