SPOTTED LANTERNFLY (Lycorma delicatula)(1^st Flying Adults = 1700 GDD): There are still some red-colored 4^th instar nymphs being observed but most areas of NJ are now seeing the adult stage of this invasive planthopper. Adult spotted lanternflies will initiate a migration period beginning in late August that will continue into the weeks of September. It is during this time that this insect will become a major nuisance in residential sites & also within more urban areas. Although spotted lanternfly adults are better hoppers than flyers, they are proficient gliders & are capable of traveling a few miles. Throughout these late weeks of summer, the insects are searching for ideal trees to feed on & then potentially lay overwintering egg masses.

Spotted lanternfly adult & 4th instar nymphs. By late August, NJ will have these stages active. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

Adult female & male spotted lanternflies. Females will typically be 15% larger than males. They will pair-up & be side-by-side during the mating weeks of the fall. Sometimes an additional male or two will also be close by, “seeking the attention of the female.” (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

Some of the most common trees selected will include tree-of-heaven, red maple, black walnut, willow, birch, & grapes. Although rare, eggs can potentially begin to be laid in August, but the majority of adult females will not start egg-laying until the end of September. Egg laying can continue to occur into the month of November. The majority of the egg masses are laid during October. With large deciduous trees, between 85-90% of eggs will be found above 10 feet off of the ground. Typically, they are laid in clusters underneath larger scaffold branches & at branch collars. Each female will usually lay two egg masses that contain 30-50 eggs each. Most adults will be killed with the onset of colder temperatures in late November. The NJ winters are rarely cold enough to kill the overwintering eggs.

Spotted lanternfly gravid female. The enlarged yellow-colored abdomen indicates this female will soon begin to lay egg masses. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

Spotted lanternfly egg masses. The white colored egg mass is only a few hours old. After less than a day the egg mass will turn a darker gray color & blend in with the bark of the tree. The masses contains 30-50 eggs each. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

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Cooley Spruce Gall Adelgid (1850-1950 GDD = galls open): Colorado spruce (especially green forms), Sitka and Oriental spruce, and Douglas-fir share this pest’s two host life cycles. Mature adult females lay eggs at the tips of branches. These eggs hatch and the immatures move to new growth and start feeding. The combined feeding and salivary secretions induce the development of a bright green, oval “pineapple” gall on the terminals (as opposed to galls at the base of new growth on Norway spruce from the Eastern spruce gall adelgids). By midsummer, the gall will turn brown and crack open, as the adelgids within mature and emerge as adults. These winged adults migrate to Douglas-fir (or another spruce) and spend the remainder of the summer feeding on the needles, covered with cottony wax.

During late July or early August the adult Cooley spruce gall adelgids will emerge from the opened brown pineapple shaped galls. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

Sometimes Douglas-fir is so heavily attacked that needles are spotted, bent, or distorted. Two or more generations can occur on Douglas-fir through the following season (Christmas tree growers will treat Douglas fir when new growth is 3-4 inches). By next fall another winged generation flies back to spruce and lays eggs for the cycle to repeat itself.

After the Cooley spruce gall adelgid winged adults emerge from the “pineapple” galls on spruce some will relocate & infest Douglas-fir needles. They will remain on this host for the remainder of the summer. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

Control by pruning out galls when seen before they open in mid-summer. Place sticky traps out in  summer (Douglas-fir or spruce) (1850-1950 GDD) to determine the timing to spray adults with insecticidal soap (+ sticker). In southern NJ some of the tip “pineapple” galls on spruce will soon open up, and the winged adults will emerged. Except to improve the aesthetic appearance of the trees, there is nothing to be gained by picking off the galls after they have opened. Future control windows will occur during the fall or early spring months, against the overwintering females located at the bases of terminal buds. Some possible treatments include horticultural oil, carbaryl (Sevin), insecticidal soap, or imidacloprid (Merit).

The Landscape Pest Notes for July 2023 contains only insect/mite pests & a couple of predators commonly seen during the month. Contained below are 16 additional pests or predators that appear in the order they are listed as follows: Pine needle scale, Fall webworm, Obscure scale, Pitch mass borer, Two banded Japanese weevil, Aphids, Cicada killer, Juniper webworm, Sapsucker, White pine weevil, Peach tree borer, White waxy lady beetle, Japanese beetle, Oriental beetle, Dogwood sawfly, & Plant leaf galls. [Read more…]

Azalea Lace Bugs (802-1029 GDD = 3^rd generation): The third generation of this pest will be in full swing for much of NJ by the end of the month. Look for the presence of nymphs (spiny, black), adults (larger, lacy wings), fecal spots (brown, shiny spots) on the underside of leaves, and stippling (feeding damage from nymphs and adults) on the leaves. Remember that the yellow stippling damage persists on the leaves until they are dropped. Look for the presence of actively feeding lace bug nymphs or adults before treating plants.

Azalea lace bug stippling symptoms on Azalea leaves. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

Azalea leaf undersides with frass spots & egg laying along mid-rib. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

When found, use horticultural oil (only if a spray can contact the back of the leaves), or acephate (Orthene) if the shrub is too dense to allow effective use of oil. Imidacloprid (Merit) applied to soils now may require 1-2 weeks before they begin to control this second generation or the beginning of the third generation (longer if soils are dry). Chlorantraniliprole is a reduced-risk insecticide that can be effective against lace bugs. Remember that stressed azaleas in full sun are more prone to lace bugs. Also, & more importantly, predators will be fewer in full-sun locations.

Azalea lace bug adult with oval shaped wings. Lace bug species having oval shaped wings will only feed on broad-leaf evergreens. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

The Landscape Pest Notes for Late June 2023 in addition to the azalea lace bugs also includes information & photographs of oak spider mites, two-spotted spider mites, pine spittlebugs, mimosa webworms, various soft scales, white prunicola scales, red-headed flea beetles & tree species prone to mid-season leaf drop.

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Boxwood Spider Mite: (GDD =450-700) (PPI = Kousa Dogwood; Cranberry Bush) This spider mite, which attacks all boxwoods, is neither a true cool nor warm season mite species. It is usually most active with intermediate temperatures during late spring & early summer. The adult is yellow-tan in color with long legs. When the boxwood mites are active, they can be found on both the top & bottom of new growth. Eggs are light yellow & overwinter on leaves & twigs. There are several generations per year.

Boxwood spider mite feeding damage results in foliage with yellow to bronze stippling, which may resemble injury caused by thrips. Both of these insects cause distinctive linear stippling streaks. These symptoms can be diagnostic when observed on foliage. With high mite populations, entire leaves may develop yellowish-white streaks; premature defoliation can occur.

Boxwood spider mite feeding symptoms. This mite species creates linear streaks on leaves. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

Boxwood spider mite symptoms that are more mild. The distinctive linear streaks are more clearly observed. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

Detected overwintering eggs are treated with dormant oils (2-3%). Although normally unnecessary, summer oils (1-2%) or insecticidal soaps are recommended to control mild mite populations. With high infestations, some reduced-risk materials include spinosad, spiromesifen, acequinocyl, & bifenazate. Examples of other materials include hexythiazoc, abamectin, fluvalinate & acephate. Be aware that fluvalinate is a pyrethroid & can promote spider mite resurgence. Acephate may only provide mite suppression.

The Rutgers Plant & Pest Advisory Blog for Early June 2023 includes some commonly observed insect/mite & disease pests within the landscape during the late weeks of spring & early weeks of summer. In addition to boxwood spider mites, the other insect/mite pests included are juniper scale, bagworm, black vine weevil, bronze birch borer, pear leaf blister mite, & beneficial predacious mite. The disease pathogens included are fire blight, oak leaf blister fungus, black spot of rose, powdery mildew & Verticillium wilt. Some suggested monitoring techniques & variables are listed between the insect/mite & disease pests.     

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