Saturday, July 26, 2014

Pest News for Week of July 28th


From: Steve Frank, Extension Entomologist

Sycamore Lace Bugs Cause Yellow Leaves

This week I have gotten three samples from the Plant Disease and Insect Clinic with sycamore lace bug, Corythucha ciliata. I had just taken some pictures of these beautiful critters last week when I was in Asheville. They really do a number on sycamore leaves and this time of year heavily infested sycamores look pretty bad. The other lace bugs that are important landscape pests are the azalea lace bug and hawthorn lace bug. Like these, the sycamore lace bug causes stippling damage by piercing the underside of leaves with its stylet and sucking out the fluids. Large yellow and gray areas develop on the top of the leaves. In some cases, most leaves on a tree can be entirely covered in stippling damage.

Sycamore lace bugs are a native insect. They overwinter as adults under bark or in other sheltered spots and become active soon after bud break. They lay eggs in leaves and complete their lifecycle in around 30 days. However, research from China, where this is an invasive pest, shows that at high temperatures this happens much faster, even twice as fast. This suggests that it could be more abundant in hot urban areas where sycamores are often planted in parking lots and along roads. My anecdotal suggests this is true. Sycamores are wetland trees and probably are not very happy in hot, sunny, dry spots, but lace bugs clearly are.

Management of sycamore lace bugs will be similar as for other lace bugs, but you are typically dealing with large trees instead of small azalea bushes or cotoneaster. Thus systemic insecticides applied as a drench can be a good option. Applications of horticultural oil should also help keep abundance low just by killing adults and nymphs that are present.

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Sycamore lace bug nymphs. Photo: S. D. Frank.

Impatiens Necrotic Spot Virus

In the last month we have had several samples come into the Plant Disease and Insect Clinic with impatiens necrotic spot virus (INSV). These have primarily been greenhouse crops like impatiens and mums, but the virus can infect over 200 plant species. It is a lethal virus spread by thrips feeding. Managing INSV is critical because it can easily over run your crop and cause long-term problems. Thrips become infected with the virus while feeding as larvae. After they pupate, thrips spread the virus to new plants when they feed as adults.

Thus, INSV management starts with thrips management. The essence is to start with sanitation. Thrips can feed on hundreds of plants so any weeds growing in or near your greenhouse can support thrips feeding and egg laying. Get rid of pet plants and mother plants. Maybe you or your grandmother want to overwinter last year’s peppers or begonias, but do not do it. These can serve as reservoirs for thrips and virus and keep your house constantly infected.

If you have INSV in the greenhouse, get rid of all plants that show symptoms and consider getting rid of all plants that thrips have fed on. Plants do not immediately show symptoms, but they can still infect thrips. So even if you get rid of plants with visible spots thrips may continue to get infected and spread the virus. Get rid of thrips with insecticide applications or ramp up an existing biological control program to get thrips under control. Now is not the time to start a biological control program. Keep an eye out for tell tale rings and spots on leaves so you can keep ahead of this virus and of course monitor for thrips with sticky cards to keep ahead of them.

You can read more about thrips management in an Insect Note and recent article in GrowerTalks.

If you would like to see thrips defend themselves from predatory mites by butt slappin’ them watch the video here:

INSV on impatiens. Photo: Robert Wick, University of Massachusetts,

For more information contact your local Cooperative Extension Center and ask for the Commercial Horticulture Agent.

Thursday, July 24, 2014

Horticulture IPM Symposium

Horticulture IPM Symposium

Here are the links to  the newly revised version of the IPM Symposium materials for those of you looking to attend:

Registration form at:

Seats will sell out quickly so be sure to get registered for yours!

For more information contact your local Cooperative Extension Center and ask for the Commercial Horticulture Agent.

Tuesday, July 22, 2014

Irrigation Summit

John Deere Landscapes Irrigation Summit 2014
Knowledge is power...AND...the key to greater profitability!!!

Do you have the technical skills to adapt to new trends in irrigation?

The 2014 John Deere Landscapes Irrigation Summit provides you the opportunity to increase your skills and improve your business.  New irrigation technologies and trends in water conservation, such as rainwater harvesting, create high-profit opportunities for the knowledgeable irrigation contractor. 

This year's summit will feature certified instructors from The Irrigation Association as well as professional business speakers addressing topics such as:
·       Pumps
·       Electrical Troubleshooting
·       Retrofitting for SMART Irrigation
·       Weather-based Controls
·       Soil Moisture Sensors
·       System Diagnostics & Locating
·       Backflow Prevention
·       Why Small Businesses Fail
Collect all 10 CEUs (8 Irrigation CEUs + 2 Business CEUs) at one location, fulfilling the NC Irrigation Contractors Licensing Board annual requirement.

Registration fee $99 per attendee.  Lunch will be provided. All events are 8:00am – 6:00pm – Full-day attendance is required to obtain the credits. Registration (sign in) begins at 7:00am at each event.

·    Wednesday, August 6, 2014  
     WNC Agricultural Center, 1301 Fanning Road, Fletcher, NC  28732 (ASHEVILLE, NC)

Register at:

For more information contact your local Cooperative Extension Center and ask for the Commercial Horticulture Agent.

Saturday, July 19, 2014

Pest News for Week of July 21st.


From: Steve Frank, Extension Entomologist

Retailers to Labels Neonic-treated Plants

Scientific American is reporting ( from Reuters that Home Depot, BJ’s Wholesale, and other smaller retailers will soon require vendors to label plants that have been treated with neonicotinoid insecticides. Neonicotinoids are among the most commonly used insecticides on ornamental crops and all crops. This class of chemicals includes imidacloprid, dinotefuran, thiamethoxam, acetamiprid, clothianidin, and others. Controversy around neonics revolves around their potential to harm bees and other pollinators. Like most insecticides, neonic are acutely toxic to bees on contact. Since neo-nicotinoids move systemically within plant tissue, they can also contaminate flower pollen and nectar that bees consume. Though this can negatively affect individual bees, the effects on bee populations are not yet known (and very hard to measure). Information about this was recently reviewed in two extension publications and a scientific paper ( Of course, there is no news that these outlets will stop selling neonicotinoids to consumers. Nursery and greenhouse growers who produce crops for retail outlets should start figuring out alternative insecticides as this trend is likely to spread.

Potato Leafhoppers Cause Crinkled Leaves on Maples

This time of year the results of potato leafhopper feeding show up particularly in nurseries. Potato leafhoppers are a native insect, but mimic retired folks because they spend winters in Florida and the Gulf coast. From there adult potato leafhoppers, Empoasca fabae (Harris) (Hemiptera: Cicadellidae) migrate between late April and early June. Female potato leafhoppers oviposit along leaf veins and clustered at the base of leaves near the petiole. Development from egg to adult takes about three weeks depending on temperature resulting in five to six overlapping generations per year.

Adult E. fabae are 3 to 3.5 mm long, wedge-shaped, and pale green with a row of six, white spots on their backs, between the wings and head. Injury is caused by salivary phytotoxins injected into the plant phloem during feeding. Damaged leaves can have necrotic margins and severe cupping or stunting referred to as “hopperburn”. E. fabae feeding on buds and meristems causes loss of apical dominance and a witch’s “broom” can develop in which many stems grow from the apical tip of nursery trees and may require extra pruning to improve aesthetics and train a central leader.

Host plant resistance can play an important role in managing E. fabae and their damage. In general, red maple cultivars that break bud earliest in spring, including clones selected from northern provenances, will support the lowest numbers of E. fabae and sustain the least feeding injury by the conclusion of the growing season. Higher levels of foliar nutrient content, particularly nitrogen, will also predispose maples to injury due to increased oviposition, nymphal survival and development rate so do not go crazy with early fertilization. Mites, aphids, and other pests also appreciate high nitrogen provided by fertilizer.

Potato leafhopper arrival can be monitored using yellow sticky cards deployed above the canopy of young maple crop or in close proximity to outer canopy foliage. These traps should be deployed in early to mid-April across the mid-southern U.S. to detect early season arrival of migratory E. fabae adults which corresponds to approximately 591 degree-days. Pyrethroids can be applied bi-weekly starting at peak trap catch. However, many applications of pyrethroids may be needed to reduce E. fabae populations and damage. Pyrethroids can also cause outbreaks of other pests like mites by killing predators in the canopy. Alternatively, recent research indicates that systemic neonicotinoid insecticides applied as a drench can provide effective leafhopper control for two years. Systemic insecticide drenches need to be applied before leafhopper arrival and can help protect natural enemies within the nursery. Even though neonics can in some cases induce mite outbreaks I think it is still a less intensive approach in terms of both labor, active ingredient, and effects on non-target organisms.
Potato leafhopper. Photo: Steve L. Brown, University of Georgia,

From: Matt Bertone, Extension Entomologist

Hoppers, Hoppers Everywhere!

I continue to get reports of numerous hopper-like insects around North Carolina. These insects, planthoppers, froghoppers and leafhoppers (Auchenorrhyncha ( Fulgoromorpha and Cicadomorpha), have been extremely abundant this year and can be found on many species of ornamental and food plants. The most common ones this year generally suck on the xylem, which is water-rich but low in nutrients. Thus, these insects produce a lot of honeydew (sugary water drops out of their anus) which can contribute to the growth of sooty mold ( Otherwise, these insects generally do little harm to plants, although leafhoppers (especially sharpshooters in the subfamily Cicadellinae) can transmit the bacterial scorch/Pierce’s disease pathogen, Xylella fastidiosa ( The following are some photos showing the most common types:

- Planthoppers (Fulgoroidea) -
Nymphal Metcalfa pruinosa, the citrus flatid (Flatidae), on a stem. Flatid planthoppers secrete a waxy field around them and rest in the middle, the barrier sometimes encompassing a great area but always housing one nymph in the center. Here the nymph was encouraged to move.

An adult Metcalfa pruinosa is grayish-blue with an orange eyes and black spots. In high numbers they can be a pest, but do not often attain such numbers.

This pale green flatid planthopper, Flatormenis proxima, is also common and its young are very similar to the one above.

Nymphs of acanaloniid planthoppers (Acanalonia) are hump-backed and usually have a tuft of wax fibers coming from their tail end. They often hop when threatened, but otherwise walk along stems of plants.
Adult acanaloniid planthoppers are leaf-like and similar to flatids, but have wings that are completely reticulate, unlike flatids whose wings are bordered by rectangular cells (see above).

- Spittlebugs and froghoppers (Cercopoidea) -
Nymphs of spittlebugs and froghoppers reside in a frothy mass of bubbles they create from gut secretions. Here they try to hide from predators while they suck on plant juices. This one is on a juniper.
Adult spittlebugs and froghoppers are usually shiny and readily hop when disturbed. Here is an adult clastopterid spittlebug. The two-lined spittlebug ( (Prosapia bicincta) is very common in North Carolina, where its young feed on grasses.

- Leafhoppers (Cicadellidae) -

Two sharpshooter nymphs (Proconiini, probably Oncometopia orbona) feeding on a new shoot of holly (Ilex). A drop of honeydew can be seen coming from the anus of the one on the right. Sharpshooters get their name from their constant ejecting of this liquid in long jets.

An adult broad-headed sharpshooter (Oncometopia orbona). These and their close relatives are among out largest leafhoppers.

The glassy-winged sharpshooter (Homalodisca vitripennis) is a famous pest, often implicated in trans-mission of Xylella fastidiosa. The white patches on the wings of this adult female are made up of microscopic waxy rods called brochosomes. They are kicked onto the eggs to apparently protect them from predators and parasites.

Cuerna costalis is another pretty sharpshooter commonly found here in North Carolina on many plants.

Unlike the previous large (~1 cm) sharpshooters, many are small and brightly colored such as this common Graphocephala versuta (~5 mm long).

And now you should be able to identify all the nymphs in this photo (on one shoot of holly)!

From: Mike Munster, Plant Disease and Insect Clinic, and Steve Frank, Extension Entomologist

Tomato Spotted Wilt Virus in Chrysanthemum

A greenhouse-grown chrysanthemum was received in the Plant Disease and Insect Clinic on July 10, 2014, and diagnosed with Tomato spotted wilt virus (TSWV) by Emma Lookabaugh. Symptoms consisted of dark leaf spots, lateral curling of the leaves at some of the spots, and at least one stem lesion. This is a common disease, but has not been diagnosed on chrysanthemum in North Carolina recently.*
TSWV symptoms on Chrysanthemum.
Tomato spotted wilt occurs on hundreds of field and crops, including peanut, tobacco, tomato, pepper, and potato, as well as on a wide range of ornamentals. In the last 6 1/2 years, we have diagnosed it on the following ornamentals from commercial sources: African marigold, angel-wing begonia, calla lily, Cyclamen, Gaillardia, Gerbera, Senecio confusus, Lisianthus, Lobelia, Madagascar periwinkle, Sedum, and Stoke's aster. Its sister virus, INSV, is a frequent problem on many ornamentals.*
A different sort of TSWV symptom on mum, from a different sample.
Both TSWV and INSV can cause a wide range of symptoms, including mottling, ringspots, stunting, and necrotic leaf and stem lesions. Both are members of the genus Tospovirus and are transmitted by minute insects called thrips*. One curious fact about this transmission is that the virus is acquired by the insect during its larval development, but then the insect itself becomes permanently infected. Of course the virus can be brought into a greenhouse with infected plants, and could be perpetuated through vegetative propagation.*
Mottling and ringspot symptoms on TSWV-infected Senecio (left) and Stokesia (right).
These strategies against TSWV (and INSV) are recommended for greenhouse flower production:

* Avoid growing vegetable transplants and flowers in the same greenhouse, and avoid growing plants of different ages together.
* Screen greenhouse vents and air intakes ( to exclude thrips from entering the greenhouse.
*  Control weeds in and around the greenhouse. Many weeds are susceptible to tospoviruses and can serve as reservoirs of virus and thrips.
* Monitor greenhouses for thrips activity using blue or yellow sticky cards, with the top 2/3 of the card placed above the plant tops. Use two cards per 5000 sq. ft. of greenhouse area.
* Use insecticides to manage thrips populations when necessary. Remove flowers from plants before treatment since the interior of flowers rarely get adequate coverage. It is important to note that some thrips populations have developed insensitivity to commonly used insecticides. In addition, no insecticide can completely eliminate thrips. Utilize the most effective chemistries wisely by rotating insecticides by mode of action (IRAC class) with each application, or at least with every generation of thrips. Always follow label directions and check that products are labeled for the intended crop. Details on insecticides for thrips management can be found in the North Carolina State University Information Note on western flower thrips ( and the University of Florida's thrips management information (

If you suspect you have infected plants, we recommend having the diagnosis confirmed by a laboratory. Large growers with recurring problems may want to keep a supply of the simple lateral-flow ELISA tests on hand. Suppliers** include AC Diagnostics ( and Agdia ( There is no cure, so all infected plants must be removed and destroyed. The potting mix of these plants should also be discarded, as this is where the thrips vectors pupate. Eliminate old stock plants as these are often sources of thrips and viruses.

More information about TSWV in the following crops is also available:

  *  Grammatical footnote: The word thrips is both singular and plural.
** Mention of trade names and companies does not imply endorsement by North Carolina State University or the Plant Disease and Insect Clinic.

For more information contact your local Cooperative Extension Center and ask for the Commercial Horticulture Agent.

Monday, July 14, 2014

Pest News for Week of July 14th


From: Steve Frank, Extension Entomologist

Bees and Neonicotinoids

Two recent publications will help growers, landscapers, retail outlets and the public understand the risks and benefits of neonicotinoid insecticides without the hype. These extension publications provide a balanced account of the current research and restrictions. Planting Garden Center Flowers is Good for Bees and Other Beneficial Insects ( was published by Dr. Dave Smitley at Michigan State University.

The second, Neonicotinoid Pesticides and Honey Bees ( by Timothy Lawrence and Walter Sheppard at Washington State University, provides an accessible literature review of research related to honey bee exposure to neonicotinoids.

Maple Spider Mite

Maple spider mites (Oligonychus aceris) are common and damaging pests of maple trees throughout the Eastern United States. These spider mites overwinter on the trunk and branches of maple trees and migrate to the underside of leaves in the spring. Once there, they use their mouthparts to pierce leaf cells and feed on cell sap. This causes fine flecking called stippling and eventually leaves turn gray or brown after heavy feeding. Maple spider mites have multiple generations per year which enables them to become quite abundant during a single season. These pests are a more serious problem in nurseries due to the close proximity of potted trees and applications of broad spectrum insecticides like permethrin. For example, our research has shown ( that applications of permethrin targeting ambrosia beetles can wipe out natural enemies and result in secondary maple spider mite outbreaks. Maple spider mites can also be abundant on landscape trees. Trees in parking lots and along roads are most likely to be infested.

Adult maple spider mite. Photo: A. G. Dale.

A hand lens or stereo microscope is necessary for correct identification of these mites, but damage is a good indicator of infestation. They are dark brown or red with hairs along their backs and have eight legs while some immature forms exhibit green coloration and have six legs. Red eggs of these mites can be found on tree limbs and yellow or clear eggs can be found on leaf surfaces. Treatment for these pests includes foliar applications of acaricides. Maple cultivars differ in susceptibility to maple spider mites and other maple pests like leafhoppers. A chapter in a recent free ibook, IPM for Select Deciduous Trees in Southeastern US Nursery Production (, describes more about management of maple pests and other tree pests. A recent article in Nursery Management ( and a fact sheet ( describes mite biology and management. This time of year trees may not be sold until fall so the condition of leaves is not as much of an issue. On landscape trees mite damage reduces fall color and summer color because leaves are gray, yellow, or brown instead of green.

Maple spider mite egg attached to tree bark. Photo: A. G. Dale.

Maple spider mite damage. Photo: A. G. Dale.

For more information contact your local Cooperative Extension Center and ask for the Commercial Horticulture Agent.