Pest News for Week of June 17th

ORNAMENTALS AND TURF

From: Steve Frank, Extension Entomologist

Fungus Gnat Larvae

This week we had reports of fungus gnats forming long lines on sidewalks and driveways. This happens after a lot of rain or heavy irrigation. In the landscape larvae feed on plant roots and live in areas with a lot of thatch or organic matter. You can read more and see a picture of the larvae-snake in an insect note athttp://www.ces.ncsu.edu/depts/ent/notes/O&T/flowers/note29/note29.html.

Tea Scale Crawlers are Active

Tea scale, Fiorinia theae, is common on camellias. It is an armored scale that lives on the underside of leaves. You can find it on almost any camellia by looking for inner leaves that have yellow spots on top. When you turn it over you will see tan canoe-shaped scale covers and some white fluff from the males. These are tough to treat because the heaviest infestations are often deep within the foliage of large bushes. To find an insect note with more information and recommendations:http://www.ces.ncsu.edu/depts/ent/notes/O&T/shrubs/note50/note50.html

Cottony Cushion Scale Activity

Cottony cushion scale, Icerya purchasi, is active much of the year. This week I found young crawlers that were being aggressively tended by fire ants on cherry laurel. The scale is most easily recognized by its oblong cottony ovisac that can reach 1 cm or longer. The rest of its lifecycle is less conspicuous though it is still one of the larger scales. Like other cottony scales, such as cottony maple scale and cottony camellia scale, cottony cushion scale is a soft scale. In the coming weeks the scale will be most easily managed as crawlers are active and exposed. Horticultural oil can be used to smother crawlers on small plants. A systemic drench can be used to treat larger plants and provide longer protection. The host list for this species is long and varied including: maple, boxwood, pecan, cedar, citrus, apple, Prunus spp., rose, and others. This week I found ovisacs on Euonymus, Nandina, and Fatsia. More information and chemical recommendations can be found in the cottony cushion scale insect note athttp://www.ces.ncsu.edu/depts/ent/notes/O&T/shrubs/note51/note51.html.

Spider Mite Damage

Although the cool season is over, damage from cool season mites is beginning to appear. I found this cherry laurel with extensive mite stippling. On the leaves there were no active mites, just lots of eggs. This is the last stand of southern red mite for the summer. They spend the hot months as eggs then come out again in fall. They feed in spring but often the damage does not become apparent until the plants face some stress in hot weather. So be sure to monitor these plants in fall. Horticultural oil may help smother the eggs, but be careful in hot weather.

In North Carolina, the most important cool season mites are the spruce spider mite (Oligonychus ununguis) and southern red mite (Oligonychus ilicis). These are among the earliest and most damaging pests in nurseries and landscapes. As their name implies, cool season mites are active in spring and fall when they suck fluid from cells on plant leaves and needles. In hot summer months these mites are dormant. However, it is summer when their damage becomes apparent as chlorophyll bearing cells die. Thus, by the time plants exhibit aesthetic damage the mites are gone and treatment is wasted.

I found all stages of southern red mites on cherry laurel, but they feed on many broadleaf evergreens such as azalea, camellia, holly, and rhododendron. With eggs juveniles and adults all present these mite populations are well underway and deserve attention from nursery and landscape personnel.

Scout plants that had mites or mite damage the previous year are likely to have them again because the mites have overwintered as eggs. You can identify plants that had mite last year by looking for fine stippling damage on the old leaves. Turn them over and look with a hand lens for silk webbing, shed skins, and mites. On broadleaf evergreens, look on the underside of leaves for the southern red mite. The most efficient method of scouting for cool season mites (and other mites) is to hold a piece of white paper or a paper plate below a branch and strike it with a pencil or stick to dislodge arthropods. Spider mites will appear as tiny moving specks about the size of the period at the end of this sentence.  

For more information and control options consult the North Carolina State University insect note at  http://www.ces.ncsu.edu/depts/ent/notes/O&T/trees/ort077e/ort077e.htm.

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

Pesticide Training - Red Imported Fire Ant Identification & Control

Pesticide Training - Red Imported Fire Ant Identification & Control

Fire Ants are on the move and coming into our nurseries, farms and landscape sites. Become better informed on controlling these pest at this workshop- coming up in July:

Fire Ant Program

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

Pest News for Week of June 10th

ORNAMENTALS AND TURF

From: Steve Frank, Extension Entomologist

Hibiscus Sawfly Damage

In Georgia last week I found severe damage by hibiscus sawfly. Larvae and adults were present on the plants I surveyed. The adults are active throughout the summer. The larvae feed on hibiscus and related plants. The larvae skeletonize leaves when they are young, but quickly defoliate plants as they grow. Contact insecticides such as bifenthrin and Orthene will kill larvae. Other insecticides such as spinosad, acetamiprid, azadirachtin and others listed can be used (http://www.ces.ncsu.edu/depts/ent/notes/O&T/shrubs/note07/note07.html). The larvae are not caterpillars so be sure to look for sawflies specifically on the label of the product you select. More information on this critter may be found at

http://www.ct.gov/caes/lib/caes/documents/publications/fact_sheets/entomology/hibiscussawfly.pdf.

New Pest: Daylily Leafminer Active Now

The daylily leafminer is a recent pest from Asia. It was first detected in 2006, but is now spread through much of the Southeast including North Carolina. I spotted some last week on a trip to Georgia. This fly lays its eggs in day lilies and the larvae produce relatively straight, vertical mines. Pruning infested leaves will help prevent the larvae from maturing and infesting new leaves. I do not know of any formal efficacy tests on this pest but other material targeting leafminers such as imidacloprid and pyriproxifen should help. A recent article about this pest is in American Nurseryman

(http://www.amerinursery.com/article-7705.aspx).

Cicadas in Nurseries and Landscapes

For folks in western parts of the state you may have periodical cicadas in your nursery or landscape. Of course this will depend on a number of things including the habitat surrounding your nursery. Areas with a lot of suburban development may have fewer than less disturbed areas.

Cicadas cause damage to trees when they lay eggs in branches. They use a knife-like ovipositor (egg inserter) to insert eggs into thin tree branches. This causes slits in the branch that could be 6 inches long or more. This long scar reduces plant aesthetic value, but also weakens branches. Scarred branches usually break and fall to the ground or break and remain hanging in the tree, but turn brown.

We have found that imidacloprid reduces oviposition in landscape trees (http://ecoipm.files.wordpress.com/2012/02/ahernfrankraupp2005jeconent.pdf). Females detect the insecticide with their ovipositor so treated trees have fewer scars and the scars are much shorter. Thus branches do not become as weak so there is less flagging. This is not to say you should treat every tree with imidacloprid. Most landscape trees over a few feet tall can withstand losing many branches with no negative effects on health. Even nursery stock could survive losing branches, but may need corrective pruning. Nursery stock can be pruned to remove scarred branches. 

Trees that are very valuable could be protected with mesh netting to keep cicadas off (http://ecoipm.files.wordpress.com/2013/06/cicada-tree-netting.pdf). This may apply to specimen trees in landscapes or to particularly expensive nursery trees. Japanese maples may be one species where shape is very important and it would be worth protection of some sort.

Cicada Management for Homeowners

With cicadas emerging, big box stores are overflowing with insecticides promising to kill periodical cicadas. This may be true. If you take a particular insecticide off the shelf and pour it on a cicada it will kill it. But these products will not ‘control’ cicadas. There are millions upon billions of them. 

There is no such thing as an insecticide that only kills cicadas. They also kill butterflies, bees, and other non-target organisms. It is important that homeowners consider the risks of these insecticides (some) compared to the benefit (none). Cicadas do not last long and pose no risk to people. Insecticides do.

The other problem with trying to manage cicadas with insecticides is that they are generally ineffective. Especially products available to homeowners provide so little benefit that the monetary cost and risk is just not worth it. If you managed to spray a whole tree with Orthene or Sevin for instance cicadas would likely colonize it again within hours or days.

Cicadas cause damage to trees when they lay eggs in twigs. They use a knife-like ovipositor (egg inserter) to insert eggs into thin twigs. This causes slits in the branch that could be 6 inches long or more. This long scar reduces plant aesthetic value, but also weakens branches. Scarred branches usually break and fall to the ground or break and remain hanging in the tree but turn brown.

Trees that are very small or that you just planted this year are at risk if they get many cicada oviposition scars. Cicadas prefer skinny branches (< 0.5 inch) so if your tree trunk is this skinny it could get damaged and this could kill your tree. Other trees will shed a few twigs and go on about their lives. You can protect trees with mesh netting to prevent cicadas from damaging them.

If you are unhappy about having cicadas on your porch or sidewalk just sweep them off. If you apply insecticide to these trapped critters (they don’t want to be on your porch) you will end up with a dead smelly pile of cicadas that you have to sweep up anyway. In addition, as you walk across the porch and sidewalk you will get insecticide on your shoes that will be carried into your house where kids and pets play on the floor. When you take your shoes off you get insecticide on your hands. Next thing you know you are eating a sandwich.

Insecticides have a place. That is to reduce economic or aesthetic damage to plants that we eat or enjoy.  Insecticide applied for cicadas won’t achieve this. So save your money and wait it out or try to enjoy it.

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

Marketing Abroad

Considering Marketing abroad to folk in other countries?  Then you might find this program useful:

http://www.susta.org/services/outreach_events_Asheville13.html

The event is on July 16th here in Asheville NC.

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

Pest News for Week of June 3rd

ORNAMENTALS AND TURF

From: Steve Frank, Extension Entomologist

Hawthorn and Azalea Lacebugs

Azalea and hawthorn lacebugs started hatching last week. Now we see a mix of adults and nymphs. Hawthorn lacebugs feed on pyracantha, serviceberry, and cotoneaster. Azalea lacebugs feed primarily on azaleas. Both cause stippling damage visible on the top of leaves and leave fecal spots on the bottom of leaves. For more information on lacebug management, see Ornamental and Turf Insect Information ENT/ort-39 at http://www.ces.ncsu.edu/depts/ent/notes/O&T/shrubs/ort039e/ort039e.htm. Imidacloprid will kill both pests, but should not be used on plants that are flowering or that will flower soon due to negative effects on pollinators.   

(http://www.xerces.org/wp-content/uploads/2012/03/Are-Neonicotinoids-Killing-Bees_Xerces-Society1.pdf).

Woolly Apple Aphids

This week we noticed woolly apple aphid infestations on pyracantha bushes around campus. These aphids 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, 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. Soap or oil should provide some control. Additional aphid management information: http://www.ces.ncsu.edu/depts/ent/notes/O&T/flowers/note38/note38.html

Flea Beetles

Redheaded flea beetles, Systena frontalis, have become a serious pest of nursery stock over the past several years. They are an especially damaging pest because they feed on roots and leaves. They overwinter as eggs in the soil. Larvae hatch in spring and begin feeding on roots. The larvae are elongate and creamy-white. Heavy infestations may reduce root mass or girdle plants. Adult redheaded flea beetles are small, shiny black, beetles with reddish to dark colored head and long antennae. They are about 1/16 of an inch long and, as the name suggests, jump when they are approached. There are at least two generations in Delaware and may be more in North Carolina.

We found adults and adult feeding damage this week. The favored hosts are Itea, hydrangea, forsythia, and knockout roses. Adult management has been frustrating for growers who find that even frequent insecticide applications do not reduce adult abundance and damage to acceptable levels. Part of this has to do with not controlling larvae since even if you kill all the adults present in a crop (which you won’t) more adults are emerging from the soil every day. Research thus far in Delaware and grower reports indicate that Talstar, Sarfari, and Flagship provide good efficacy as foliar applications, but do not have long residual activity.

Recommendations for the use of chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by North Carolina State University, North Carolina A&T State University or North Carolina Cooperative Extension nor discrimination against similar products or services not mentioned. Individuals who use chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. For assistance, contact an agent of North Carolina Cooperative Extension.

For more information contact the commercial horticulture agent at your local Cooperative Extension Center.  

Pest Alert for Week of May 27th

ORNAMENTALS AND TURF

From: Steve Frank, Extension Entomologist

Cottony Maple Leaf Scale Eggs

Cottony maple leaf scale is one of several cottony scales in the genus Pulvinaria. You can find these now on their most common hosts: maple and dogwood. Stand under a tree and look up and you will see cottony masses about the size of a cotton swap stuck to the bottom of leaves. These are the egg masses. They each contain many hundred eggs that are hatching as we speak. The crawlers will settle and feed on the leaves all summer then migrate back to branches in fall before leaf-drop.

Cottony Cushion Scale

Cottony cushion scale is an exotic pest that became a very important pest of citrus. However, it is quite generalist and does affect several ornamental plants such as nandina, euonymus, boxwood, rose and others. Cottony cushion scale is very noticeable when female egg sacs are present. They are present now and most of the time there are several overlapping generations per year. Cottony cushion scale is an example of a relatively successful biological control program in the U.S. The vedalia beetle was captured in its homeland of Australia and released to bring the pest under control. Although cottony cushion scale can still be found and remains a pest it is often kept in check by this wide-spread beetle. These are in a different family (Mararodidae) than other soft scales (Coccidae). However, control measures are similar to those outlined in the soft scale management note:

http://www.ces.ncsu.edu/depts/ent/notes/O&T/shrubs/note156/note156.html

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Recommendations for the use of chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by North Carolina State University, North Carolina A&T State University or North Carolina Cooperative Extension nor discrimination against similar products or services not mentioned. Individuals who use chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. For assistance, contact an agent of North Carolina Cooperative Extension.

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

Pest News for Week of May 20th.

ORNAMENTALS AND TURF

From: Adam Dale, Graduate Student, and Steve Frank, Extension Entomologist

Painted Maple Aphids

Painted maple aphids are common on maple trees and do not generally require treatment. However, you will probably see them if you are scouting for scales or other more important pests. They are quite colorful up close. We sent out an alert and blog post (http://ecoipm.com) this week with a full life history description and pictures from under a dissecting scope. As with all aphids and other phloem feeders you can see shiny honeydew on leaves below where aphids are feeding. The tree in the picture below also has a severe scale infestation so the honeydew you see was not all from these aphids. 

From: Steve Frank, Extension Entomologist

Ambrosia Beetle Trapping

This week did not find any ambrosia beetles in our traps and did not get any attacks on our experimental trees. So we may be out of the woods for this year. Since this week was cool I will keep trapping one more week to be sure we don’t get surprised by latecomers who were waiting for warm weather. Check the blog or twitter alerts for updates.

Cankerworms Gone!

Cankerworms have finished feeding for the year and are no nestled safely underground as pupae. At this point you should take stock of which trees were defoliated in your yard or on the properties you manage.  Heavily infested trees will also be heavily infested next year because the caterpillars pupate under the tree they were born in then climb back up as adults in fall. Consider banding these trees and adjacent trees to prevent consecutive years of defoliation.

Cankerworm information: http://ecoipm.com/research/cankerworm-project-home/

More banding information: http://www.cabarruscounty.us/government/departments/cooperative-extension/lawn-garden/Pages/Cankerworm-Prevention.aspx

Elm Pests Get Going

Right now a lot is happening on elm trees. For those of you who still have elm trees you can look for elm leaf miner, Fenusa ulmi, and woolly elm aphid, Eriosoma americanum. Elm leaf miner is a sawfly that lays eggs in elm leaves. The larvae mine tissue creating blotchy, brown translucent areas on the leaves. In late spring the larvae exit leaves, drop to the ground and borrow an inch down to pupate.  Affected leaves will remain on the trees and become brown as mined tissue dies. They may drop prematurely. This time of year you can find a few adults left but mostly you will find larvae in various stages of development. Mines are small so far but expand rapidly. Imidacloprid and Orthene can be used to kill larvae in mines, but they are protected from contact insecticides such as bifenthrin. If adults are present in your area, foliar applications of these products can reduce oviposition.

Woolly elm aphids are an interesting aphid that manipulates host foliage to create a shelter. The foliage is not altered into a true gall like those on witch hazel but as you can see in the picture that are pretty snug and protected from the elements. These aphids use serviceberry (Amelanchier spp.) roots as alternate hosts. They overwinter as eggs on elm bark. A female aphid emerges as elm leaves are expanding. She feeds on the underside of a leaf and at maturity produces 200 eggs. The infested leaves begin to curl and accumulate waxy debris that makes the aphids look woolly. Mid-summer a winged generation develops that migrates to Amelanchier trees. These colonies of twisted leaves can be easily pruned out. In the case they are over abundant or there are other pests present an insecticide application may be warranted. 

Lady Beetles

Lady beetles seem particularly abundant this week. On a single bush I found several dozen this morning. There are two stages pictured: larvae and pupae. I figure everyone knows what adults look like. Lady beetles and their larvae feed on many soft-bodied insects such as aphids, mites, scales, caterpillars, and many others. Avoid applying insecticide applications when lady beetles are present. Adult lady beetles typically lay eggs only where there is prey. So if you see lots of lady beetles you may need to take a look at what else is on your plant.

Slugs in the Landscape and Nursery

After a wet couple weeks I have seen a lot of slug damage to annuals and perennials in landscapes. Slugs thrive in moist area such as around dripping water spigots and irrigation heads. With all the rain we have had though they are everywhere that is shady and humid. Management of slugs begins with making the habitat less suitable for them by reducing moisture, decaying vegetation, and debris or pots they can hide under. Of course, reducing pots in not an option at nurseries. There are some baits that can be broadcast in slug prone areas. These include products containing metaldehyde or methiocarb (Mesurol) which are carbamates toxic on contact or ingestion. These products are also toxic to pests and children so baits should be inconspicuous and sprinkled over the area rather than arranged in piles that pests and children will notice. Iron phosphate (Sluggo) also has good efficacy against snails and slugs. It also has less mammalian toxicity. Review the below websites for articles on slugs and slug management:

http://www.oan.org/associations/4440/files/digger/Digger_APR_2011_p49-53.pdf

http://www.ipm.ucdavis.edu/PDF/PESTNOTES/pnsnailsslugs.pdf

New Articles About Nursery and Landscape Pests

We have a new article in Nursery Management on spider mite identification and management and a new article in American Nurseryman about ambrosia beetles and the most current management strategies. These articles and other industry publications are posted on our Industry Publications page:

http://ecoipm.com/extension/extension-resources/industry-publications/

Gloomy Scale Crawlers are Active

Gloomy scale, Melanaspis tenebricosa, is an armored scale that is found on maples and other tree species. It becomes very abundant on landscape maples 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. I have never found one that didn’t have it! Crawlers of this scale are active now and can be seen on bark and under scale covers. Control of this scale is complicated because crawlers emerge over 6 to 8 weeks so it is impossible to treat all the crawlers at once with horticultural oil or other contact insecticide. This is as opposed to scale such as euonymus scale in which all crawlers are produced within a narrow window of 2 weeks or so. However, horticultural oil can still be applied to kill gloomy scale because it will kill some adults also. We have found even a single application dramatically reduces scale abundance. Several systemic products are available to provide longer control of even late stage scales. These include Safari, TriStar, and Distance though it is important to note that imidacloprid (Merit) is not effective on armored scale. More information on armored scale control can be foundhttp://www.ces.ncsu.edu/depts/ent/notes/O&T/shrubs/note157/note157.html.

To see an overview of gloomy scale on urban trees watch our short video:http://www.youtube.com/watch?v=1Fg-ZPkJwRA&feature=youtu.be

Lecanium Scale Crawlers!

Oak and European fruit lecanium scale are one of the largest soft scales in our area. Scale ovisacs are brown and rounded reaching 6 mm in diameter. This is the most noticeable stage and is present right now. As members of the soft scale family Coccidae, lecanium scales produce honeydew that can cause sooty mold on oaks or plants below. Oak lecanium scale primarily infests oaks trees. However, European fruit lecanium can infest many tree species including oaks. They are impossible to tell apart without a microscope (even then it is hard). Large populations can reduce growth and vitality especially in newly planted trees. 

Eggs are present now under adult scale covers and crawlers are beginning to hatch. The crawler stage should be targeted for best efficacy. On trees small enough to treat foliage horticultural oil can be used. On larger trees a systemic such as dinotefuran can be applied as a drench or trunk injection. This scale is not easily eradicated and optimal control measures are still unclear. It is attacked by many parasitoids and predators that can reduce scale abundance if protected from insecticides. A short video by graduate student Emily Meineke describes the scale biology (http://www.youtube.com/watch?v=tD6I7P6BdKU). You can see another video about her research (http://www.youtube.com/watch?v=UnhoEFnNHxo).

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

Plant Evaluation Symposium

Sustainable Beauty: Landscape Plants That Thrive in the Southeast

Enjoy a full day of ornamental plants selected for their unique flowers, foliage, fall color, bark,  drought tolerance, and adaptability to changing climate conditions. Researchers, plantsmen, and extension faculty from across the South will highlight native and non-native woody and herbaceous plants that will enrich and extend your garden’s seasonal interest.

Garden Centers should invite their customers!

For more information and to access a copy of the brochure click on the following link:  Symposium-Brochure

"The brochure is best viewed using Adobe Acrobat reader.  Some browser plug-ins make the text hard to read with the background, so try Adobe Acrobat if you have trouble viewing it."

To Register on-line simply visit our NCSU Go Links


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

Flooded Fields and Pest Pressure

After the recent rain fall and the flooding that has occurred many of the trees in your fields will have an increased level of pest pressure particularly from various water molds as well as Granulate Ambrosia Beetle GBA.  It would be a good idea to do extra monitoring for pathogens as well as plan on spraying for the GBA.


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

Pest Alert for Week of May 5th

ORNAMENTALS AND TURF

 

From: Steve Frank, Extension Entomologist

Midge With An Eye on Maples

The ocellate gall midge, Acericecis ocellaris causes an ocellate (single-spotted), pale green to yellow, often bright red-margined gall. Galls are 5 to 6 mm in diameter and occur primarily on foliage of red maples but also A. saccharinum, A. spicatum, and A. pennsylvanicum. I found galls this week on trees in central Georgia so if you have not seen the here yet you will soon. Galls typically appear in May and contain a single, translucent midge larva. Larvae exit the gall and drop to the ground to overwinter as pupae. These are actually quite attractive critters that could even improve the appearance of trees. Just think, if someone bred a tree with yellow and red eye-shaped dots it would be all the rage. That said, these midges usually only occur a few at a time and will not harm tree health. Find out more about maple pests in a free e-book: http://ecoipm.com/extension/extension-resources/.

Rose Sawflies

I found these sawflies on knockout roses this week in Georgia. I also found some on my roses in Raleigh that were slightly smaller. They are probably the curled rose sawfly, Allantus cinctus, but I am waiting on a positive identification. In any case you can look for damage to leaves by these and other sawflies. Small larvae typically skeletonize the leaves. Larger larvae consume entire leaves. Scout to this damage and also for feces which are a sure sign of something feeding on your plants. If infestations are large a contact insecticides such as a pyrethroid or acephate can be applied. Conserve is also labeled for sawflies. Small infestations in home landscapes could be managed with horticultural oil or insecticidal soap.

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