Southeastern Ornamental Horticulture Production and Integrated Pest Management

News alerts and tips from Southeastern universities.

Yellow poplar weevil outbreak

Originally posted on

I was in Northwestern Pennsylvania last week and found tulip poplar trees with leaves that had brown dried edges and small brown spots. From a distance the trees looked like that had leaf scorch or some disease. It turned out they were covered in small black to blue weevils called yellow poplar weevils, Odontopus calceatus. I have never encountered these in Raleigh. The authoritative Insects that Feed on Trees and Shrubs by Johnson and Lyon has a short entry on this critter. Apparently theoverall distribution is from New England south to Louisiana but are most common in central Appalachia. This fits with the location of the trees I found and with reports from Cliff Ruth that these are common in the mountains of NC this year.

Yellow poplar weevils and feeding damage. Photo: SD Frank

A quick google search turns up dozens of news articles from PA and WV describing outbreak populations and damage this year.

There is one generation per year. Adults overwinter in leaf litter fly to trees in spring and lay eggs in early summer. A report from Auburn describes the life cycle in the South. Larvae and adults feed on leaves causing blotch mines and holes. They pupate within leaf mines. New adults emerge in mid-summer, feed a little, then become scarce until the following year.

Brown leaves and twigs without leaves on a tulip poplar infested with yellow poplar weevils. Photo: SD Frank

These probably do not threaten tree longevity or growth especially if they just turn up occasionally. They will make your tree look a little ragged though. Since there is one generation per year if you could dislodge or kill the bulk of them with horticultural oil or soap you would reduce the damage. A pyrethroid would also kill adults but maybe not all the larvae in mines. Other beetle-active systemic products like neonics or Acelepryn should kill the beetles and larvae but it may be late in the year to try and make drench applications you could try a foliar application.


Imported willow leaf beetles

Imported willow leaf beetle adult. Photo: SD Frank

Reposted from

Imported willow leaf beetle (Plagiodera versicolor) are common on willows in landscapes and natural areas. Most of year adults and larvae are feeding on willows. The adults are iridescent black to blue and about ¼ inch long. The larvae are dull gray. The eggs are yellow and resemble lady beetle eggs.

The adult beetles overwinter outdoors under bark or in leaf litter. They and emerge from hibernation sites in spring around the time willow leaves start developing since adults prefer new leaves. Adults and larvae skeletonize leaves, leaving larger veins intact. This gives trees a brown cast as damaged leaves crisp in the sun. In some cases though they can defoliate trees like the one I pass walking to work each day. This tree has been defoliated for the past 5 years and this year is dead.

Pubescent varieties of willow may be less affected than glabrous varieties. Also when you inspect infested willow trees you often see a lot of lady beetle larvae, pupae, and adults that eat the eggs. Thus, if the habitat is suitable to sustain these and other predators insecticides are often not necessary.

Insecticides labeled for leaf feeding beetles such as spinosad, imidacloprid, and chlorantraniliprole, and others in the NC Agricultural Chemical Manual can be used if needed. Unfortunately, these beetles are here to stay so efforts to prevent any damage to willows is in vain. If you plant a willow in a landscape these beetles and some damage are practically guaranteed. The goal should be to keep populations below a level that cause substantial defoliation.

Check out Dr. Raupp’s bug of the week post on willow leaf beetle for cool info on how they defend against predators. If you like old drawings check out this 1940 USDA Bulletin.

Woolly apple aphids

Re-posted from

Update: Today while walking around the neighborhood I saw lots of migrating woolly aphids, probably woolly elm

Woolly (Eriosoma sp.) aphid migrant. Photo: GG Frank

aphid, floating through the air. They look like little white troll dolls with white tufts of ‘hair’. Species in the genus Eriosoma migrate between two hosts. Woolly apple aphids have a complicated life history. They can overwinter on the as nymphs on roots of rosaceous plants and on elm as eggs. In spring eggs hatch and eventually adults migrate from elm to rosaceous hosts. Then it seems some of these migrate down to overwinter on roots but others must migrate back to elm. It is not well understood. Woolly elm aphids  (Eriosoma americanum) feed on elm leaves in spring then adults migrate to Amelanchier spp. in early summer. These may be what we are seeing now. In any case keep your eyes out for white floating tufts and try to grab one for a close look.

Woolly apple aphid (Eriosoma lanigerum) infestations on pyracantha bushes around campus. These produce cottony fluff along the branches. When you brush away the fluff (really it is wax the aphids produce) you will see hundreds of pink or grey aphids crawling around.  Woolly apple aphids have been out for a month or so now but are becoming very noticeable now. Infestations for multiple years produce large leafless patches on bushes. The aphids cause galls to form on branches and branches become black from sooty mold.

Bare patches and black deformed twigs from woolly apple aphid feeding on pyracantha. Photo: SD Frank

Pyracantha is also host to hawthorn lace bugs which are active now. The beautiful critters cause stippling on leaves. Between the two pests, pyracantha often looks pretty bad a lot of the time. One benefit may be that I noticed hundreds of lady beetle pupae on the the infested bushes I was photographing. Soap or oil should provide some control more information from WSU and eXtension.

Woolly apple aphids. Photo: SD Frank

Gloomy scale crawlers hatching

 Originally posted on

Adult gloomy scale. Photo: SD Frank

Gloomy scale, Melanaspis tenebricosa, is an armored scale that feeds on maples and other tree species. It becomes very abundant on red maples on streets and in landscapes and can cause branch dieback and tree death in some cases. It is not unusual to find trees with nearly 100% of their trunk covered in scale. Street trees are particularly prone to gloomy scale. Crawlers of this scale are active now and can be seen on bark and under scale covers. One of the reasons we have found this to be such a pest is that female gloomy scales produce about 3 times as many eggs when they live on relatively warm trees (like in a parking lot) than when they live on cooler trees (like in a shady yard). This amazing work is outlined in a recent paper by Adam Dale.

Control of this scale is complicated because crawlers emerge over 6-8 weeks so it is impossible to treat all the crawlers at once with horticultural oil or other contact insecticide. This is different than in other scales, such as euonymus scale, in which all crawlers are produced within a narrow window of 2 weeks or so. Adam Dale took a video of some gloomy scale crawlers so you can get an idea of how tiny and nondescript they are. This may also give you an idea of why scales are so vulnerable at this stage to the environment, predators, and insecticides like horticultural oil. Once they produce their thick waxy cover they are much less vulnerable to all these factors.

See a video of scale crawlers here.

Bagworms hatching in Raleigh, NC and on conifers near you

If you have conifers or other plants that seem to have grown weird, dangling pinecones, look again because you have bagworms. Bagworms have been hatching for the last week or so. You can find the tiny caterpillars with tiny upright bags anywhere there are bags left from last year.

First instar bagworms with tiny upright bags. Photo: AG Dale

The Bagworm, Thyridopteryx ephemeraeformis, is a very common pest of conifers and other ornamental plants throughout the eastern United States. These pests overwinter as eggs within the mother’s bag. Larvae emerge from the bag during the May and June (depending on location and temperature). The larvae crawl or drift via silk strands to nearby foliage where they begin to feed. Bagworms are relatively sedentary during their lifetime, most often remaining on the same tree until they pupate. Adult females are wingless and never leave the tree. Male bagworms develop into a small brown moth.

Bagworms feed on plant foliage and heavy infestations can defoliate trees and shrubs. Young caterpillars produce a silk bag on their posterior end that gradually collects plant debris. This creates a bag covered in pine needles or leaves that protects them from predators and looks (sort of) like a pinecone. Since they don’t move much as larvae and the females don’t fly, they can build up dense populations. Since they are so camouflaged and protected from insecticides, management of these insects can be difficult and time consuming. One of the most effective, yet time consuming methods of treatment are hand-picking or cutting the female pupae bags off of the branches. When this is impractical or impossible, there are chemical control options available that should be applied when caterpillars are young (now) because they are more vulnerable. As with many other pest insects, bagworms are susceptible to predation from parasitoids and birds which can also assist in their control. Find more pest information and blog posts at

We’re Back for Spring

Hello everyone,

We took some time off while the blog was undergoing a facelift, but now we are back and will be posting as time allows and as we discover material we believe would be interesting and useful to you.

We hope you have a great spring season!

Matthew Chappell

(blog administrator)