Watch white peach scale – crawlers coming soon

White peach scale (Pseudaulacaspis pentagona) is an armored scale common on many landscape plants and fruit trees. It has a wide host range including over a hundred plant genera such as Buddleia, Camellia, Clematis, Cornus, Euonymus, Hydrangea, Ilex, Ligustrum, Prunus, and many others. The most common host of samples submitted to the PDIC here at NCSU is cherry laurel (Prunus laurocerasus). Cherry laurel is an exotic species which of course is installed in nearly every new landscape I see.

White peach scale females and males on cherry laurel. Photo: SDF

Like most armored scales white peach scales are sexually dimorphic. The females are waxy bumps on twigs but the males grow wings and look like an actual insect. The males emerge from ‘pupal cases’ (not technically pupae). Twigs become covered with the fluffy white pupal cases. This is the easiest time to see and diagnose white peach scale infestations.

Female white peach scale with cover removed surrounded by fluffy white male pupal cases. Photo: SDF

Of course the males come out to mate. Two weeks after the males emerge females will begin producing eggs and crawlers will start hatching. Scouting for the males, even though they do not feed, gives you a head start to plan your management approach.

White peach scales have 3 to 4 generations per year. Infestations are often concentrated on particular branches since scales do not move very far. Dense infestations can kill the individual twigs they are on. Minor infestations in landscapes should be monitored. You can probably inspect most cherry laurels and find some of these. That doesn’t mean you need to treat them; they can just hang out in low densities for years controlled by natural enemies. Plant stress and insecticide applications, like mosquito sprays, could increase the likelihood many armored scale species become problems.

March 7th, 2017|Categories: Landscape IPM|Tags: , |

Early spring flowers=Insecticide risk for bees

Barberry is very attractive to bees and is blooming early in Raleigh. Photo: SDF

Spring in Raleigh is almost a month ahead of usual (is usual a thing anymore?). This means we’ve had red maples flowering since mid-January. More importantly they have been visited by bees the whole time. Not just honeybees either. We have been trapping bees in red maples for the past month or so and found honeybees, bumblebees, and smaller Andrena spp.

Today I noticed hollies flowering along with redbuds, barberry, and azaleas. Surely boxwoods, nandinas, cherry laurels, and other species attractive to bees are not far behind (or is it ahead?). This time of year folks making preventive insecticide applications may not usually think about bees and whether plants are flowering. Many insecticide labels restrict applications when bees or flowers are present.

Hollies have small flowers that many people don’t notice but bees love them. Photo: SDF

Neonicotinoids, like imidacloprid, have been in the news but label restrictions to protect bees are common on most insecticides including other landscape and nursery favorites like bifenthrin and orthene. To be safe: read the labels, don’t make applications when bees or flowers are present, and delay systemic insecticide applications until after flowering. A recent HRI publication and new bulletin and article from Michigan State University could help.

March 1st, 2017|Categories: Landscape IPM, Pollinators|Tags: |

Warm days likely bring ambrosia beetle attacks

Frass tooth-pick from adult ambrosia beetles boring into trees. Photo: SD Frank

With several days of warm weather be on the look out for ambrosia beetles in your nursery. You are trapping right?

Keep checking those traps. I already have reports of a few beetles trapped in the eastern part of the state. Do not over-water your trees. Media moisture over 50% makes trees more attractive to beetle attacks. Many species, like dogwood, are never attacked when media moisture is below 50%.

Read up on our past ambrosia beetle posts, industry publications, new media moisture thresholds, and a review in the Journal of IPM.

February 21st, 2017|Categories: Nursery IPM|Tags: , |

iBook for Greenhouse Pest Identification

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The 2nd Edition of “Insect and Mite Pests of Floriculture Crops: Identification Guide” by Matt Bertone, Steven Frank, and Bryan Whipker is now available from iTunes. This guide is designed so growers, extension personnel, or anyone else can identify common arthropod pests on greenhouse crops.

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This new edition covers aphids, fungus gnats, leafminers, mealybugs, mites, scales, shoreflies, thrips, and whiteflies. Concise biology and management information is paired with galleries of fantastic photographs by Matt Bertone.

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Galleries feature multiple views of the pests, their damage, and their natural enemies. The final edition will be out in 2017. And guess what? Its free so download it now! Thanks to a grant from the Fred C. Gloeckner Foundation.

November 10th, 2016|Categories: Greenhouse IPM|Tags: , , |

Highlights of the 20th Ornamental Workshop

Frank Hale and Andrew Loyd in costume (not mandatory btw) during the Wednesday night social. Photo: Suzanne Wainwright-Evans.

Frank Hale and Andrew Loyd in costume (not mandatory btw) during the Wednesday night social. Photo: Suzanne Wainwright-Evans.

Now over 40 years old, the Ornamental Workshop convened for three beautiful days in late October. One hundred and twenty-three university researchers, extension personnel and representatives from agrochemical companies, biological control companies, tree care companies, public gardens, and others all converged in Hendersonville, NC to geek-out on the pests and diseases of ornamental plants.

Engaged participants soaking up knowledge.

Engaged participants soaking up knowledge. Photo: Suzanne Wainwright-Evans.

Our keynote speakers, Adam Dale (University of Florida) and Steve Oak (USDA FS), started big with presentations about how climate change and urbanization affect insect and disease biology and management. For the next 3 days we had talks and workshops on everything from the latest research on exotic pests like emerald ash borer, crape myrtle bark scale, sudden oak death, and rose rosette, to new innovations in extension delivery. We covered nurseries, greenhouses, chemical control, biological control, new pests, old pests, you name it. We even had a workshop on macrophotography by Matt Bertone (NCSU). You can view the whole program to see what you missed.

Participants Cliff Sadof, Brian Kunkel, Gerald Adams, and Carlos Quesada 'networking' on a hike.

Participants Cliff Sadof, Brian Kunkel, Gerald Adams, and Carlos Quesada ‘networking’ on a hike. Photo: Suzanne Wainwright-Evans.

Of course we never work too hard at the Ornamental Workshop even though ‘work’ is in the name. Each night we gather for drinks and snacks for networking (there is that ‘work’ again) and catching up with friends. The highlight for some folks is Wednesday when we take the afternoon off for a mushroom foray and hiking. This naturally inspires some to attend the social Wednesday evening dressed as their favorite insect or disease. This without a costume can decorate a moonpie to honor their favorite pests.

Moonpie insects and diseases ready to be judged. Photo: Suzanne Wainwright-Evans

Moonpie insects and diseases ready to be judged. Photo: Suzanne Wainwright-Evans

I personally thank all the participants and sponsors for another great workshop. If you want to attend in 2018 watch the website, Facebook page, or join the listserv. If you know someone who should attend this meeting please pass along this post.

Morning at the Ornamental Workshop. Photo: SD Frank.

Morning at the Ornamental Workshop. Photo: SD Frank.

November 9th, 2016|Categories: Landscape IPM, Nursery IPM|Tags: |

National Ornamental Workshop: Register Now

For 40 years people have met in the mountains of North Carolina to talk about pests and pathogens of ornamental plants. It started as a few professors chatting about new pests problems by day and playing music by night. It has grown considerably; the last Ornamental Workshop in 2014 attracted 130 people from 35 states. Attendees included academics, extension personnel, members of the agrochemical and biocontrol industries, non-profit organizations, and others.

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This year the Ornamental Workshop is October 24-27. Although the meeting has grown it is still fun and informal. We mix presentations and discussions. Sometimes entomologists and plant pathologists meet separately to focus on the intricacies of each discipline. We also come together for sessions important to both like arthropod transmitted plant pathogens and extension innovation. What’s more it’s held at a secluded mountain retreat with nightly socials to encourage (force?) networking and hopefully making new friends.

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The Ornamental Workshop is a place for people to share new research, extension, and pest management practices with other research and extension professionals. There is no trade show, no pesticide credits, and no formal training. But, if you have ideas and information to share this is the place to do it. Register and submit your presentations here. Contact Steve Frank (sdfrank@ncsu.edu) with questions.

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September 1st, 2016|Categories: Lab Happenings|Tags: , |

New paper: Media moisture thresholds for ambrosia beetle IPM

Ambrosia beetles are among the most damaging pests of nursery. The main culprits are granulate ambrosia beetle (Xylosandrus crassiusculus) and the black stem borer (X. germanus). We have worked on ambrosia beetles for several years to find ways to reduce damage and insecticide use. Recently though, in collaboration with Chris Ranger at USDA ARS in Wooster and other scientists, we finally got to the root of the problem: why do ambrosia beetles attack nursery stock to begin with?

Chris and other collaborators started down this road with the realization that when trees get too much water they release ethanol through their bark. And what is the lure in ambrosia beetle traps?: ethanol.

Flooded trees produce ethanol which is the lure as in ambrosia beetle traps use ethanol

Flooded trees produce ethanol which is the lure in ambrosia beetle traps use ethanol. Photo: SD Frank

The question then became “how wet is too wet?” If nurseries could prevent trees from getting ‘too wet’ water maybe they could stop ambrosia beetle attacks all together. To answer this question we grew Florida dogwoods in containers and maintained 10, 30, 50, 70, or 90% media moisture throughout the spring. It turns out that trees above 50% media moisture got hammered by ambrosia beetles and those below did not get attacked at all. So, at least for dogwoods, we recommend a media moisture threshold of 50% or below to reduce ambrosia beetle attacks.

Experimental trees with covers to help regulate media moisture. Photo: SD Frank

Experimental trees with covers to help regulate media moisture. Photo: SD Frank

Next we measured media moisture at 6 cooperating nurseries each spring for two years. Unfortunately, containers at most nurseries were above the 50% threshold during peak ambrosia beetle activity in early spring. Thus, trees in these nurseries smelled sick to ambrosia beetles and were susceptible to attack.

Reducing media moisture in spring is a challenge because the weather is cool and often wet and trees are not transpiring. That said, sometimes we found irrigation systems were operating during ambrosia beetle season when they probably weren’t required. More research is required to develop horticultural tactics, such as new substrates, to reduce spring media moisture. In the mean time though growers can add the media moisture threshold of 50% to their IPM toolbox to use in combination with other tactics like trapping and insecticide applications.

Frank, S. D., and C. M. Ranger. 2016. Developing a media moisture threshold for nurseries to reduce tree stress and ambrosia beetle attacks. Environmental Entomology 45: 1040-1048.

 

August 23rd, 2016|Categories: Nursery IPM|Tags: , |

Crape myrtle bark scale: New tree pest has arrived in NC

A couple years ago I began warning about a new pest that was spreading throughout crape myrtle country. Now, the crape myrtle bark scale has arrived. From the severity of the infestation it looks like it actually arrived many years ago but now it is “official.” This is bad news because crape myrtles are one of our most commonly planted trees in yards and along streets. Crape myrtles are typically almost maintenance free (unless you top them) but now they will require pest management to stay healthy and beautiful.

Crape myrtle bark scale. SD Frank

Crape myrtle bark scale. SD Frank

Female scales produce fluffy white filaments that cover their body. In spring they produce eggs beneath their body then die. Tiny crawlers hatch from the eggs, settle in their new spot, and begin producing white filaments. They have at least 2 overlapping generations. At low density, crape myrtle bark scale feeds in rough areas around branch collars but as the population increases all the bark may be covered. These scales are most often noticed because trees become covered in black sooty mold. At first many people assume this is from crape myrtle aphids so the scales may go undetected. If you notice unusually heavy honeydew and sooty mold on crape myrtles take a closer look at the bark.

Crape myrtle bark scale is a felt scale related to azalea bark scale and oak eriococcin scale. They feed on phloem like other “soft scales”, thus the honeydew. Even though there is not a lot of efficacy data available drench applications of neonicotinoids are typically effective against phloem feeders. However, since crape myrtles flower continually and attract a slew of pollinators be sure to read the labels for restrictions on using them. Insect growth regulators such as pyriproxyfen and buprofezin are effective for many other scales and may be a good option. Horticultural oil, especially the heavier dormant rate, can reduce scale abundance also.

Crape myrtle bark scale on a rough branch collar. SD Frank

Crape myrtle bark scale on a rough branch collar. SD Frank

There are many subdivisions and streets in North Carolina lined with crape myrtles. Inspect these trees to determine when they become infested. Also consider diversifying the tree planting of your neighborhood. Luckily this pest does not kill trees outright like some other exotic pests increasing tree diversity helps ensure all the trees are not infested or killed at once by a single pest.

August 8th, 2016|Categories: Landscape IPM|Tags: , |

Emerald ash borer cropping up in new NC counties

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Silhouette of an ash tree infested with EAB showing classic thinning in the crown. Photo: David Cappaert, Bugwood.org

Emerald ash borer is continuing to spread through NC. So far this summer, it’s already been found in four new NC counties (Davidson, Forsyth, Swain, and Yancey). At this rate, the NC Forest Service is anticipating a lot more findings and is asking folks to keep their eyes peeled for tell-tale signs of beetle activity.

Check out this month’s Forest Health Note for more info on EAB in NC.

July 21st, 2016|Categories: Urban Ecology|Tags: , , |

Maple Shoot Borers Damaging Maples in Nurseries

This is a guest post by our PhD student Larry Long.

MSB Flagging (Long)

Flagging of apical shoot and frass expelled from larvae developing inside the stem and beneath the lateral leaves. Photo Credit: Larry Long, NCSU

Maple shoot borers (Proteoteras aesculana) are common pests of red maples in nurseries. This caterpillar causes flagging and dieback of the apical shoots of maples (Acer spp.). It is too late this season to manage this pest or damage with insecticides but recognizing the damage could inform your management next spring. Maple shoot borer adults are small nondescript moths that lay eggs on maple stems near expanding buds in early spring. After hatching the caterpillar burrows into the growing shoot where it feeds on the vascular cambium. As the larvae develops it expels frass and silk from the hole through which it entered the stem. Young stems and leaves above the point where the larvae entered eventually die.

Mature larvae exit the shoot then pupating on the ground. There is no evidence of summer season egg laying so it is thought that upon emergence from their pupae the new moths seek overwintering sites.

Monitoring for damage by this pest is not very useful because by the time damage occurs management is impractical. However, if a high proportion of plants are infested this year it could warrant preventive insecticide applications next spring. To confirm that damage is from maple shoot borers and not another pest like potato leafhoppers, cut open flagging stems to see if they are hollow and if larvae are present. The larvae are a tan to cream-colored with a dark head capsule.

Dissected maple stem showing larvae living inside. Photo Credit: Matt Bertone, NCSU

Dissected maple stem showing larvae living inside. Photo Credit: Matt Bertone, NCSU

Preventive management entails applying pyrethroid insecticide from just before bud break until shoots have flushed their first two pairs of lateral leaves. Since this is in early spring you may be making these applications anyway for ambrosia beetle management so there is no need to spray extra just for maple shoot borer. Preventive applications are important because once symptoms appear it is too late for treatment. Damaged shoots should be pruned and a new leader trained to correct tree form.

Dieback or ‘flagging’ caused by maple shoot borer. Photo Credit: Larry Long, NCSU

Dieback or ‘flagging’ caused by maple shoot borer. Photo Credit: Larry Long, NCSU

See our guides for IPM of of trees and shrubs in nurseries on our extension resources page.

May 13th, 2016|Categories: Nursery IPM|Tags: , , |