Pest Alert for Week of April 28th

ORNAMENTALS AND TURF PESTS

From: Steve Frank, Extension Entomologist

Ambrosia Beetles Still Active

Just a quick update in case you are not trapping ambrosia beetles. We are still finding a lot of beetles in traps. This week we had 132 attacks on one tree in our experimental nursery. Management of ambrosia beetle (http://www.ces.ncsu.edu/depts/ent/notes/O&T/trees/note111/note111.html) damage requires pyrethroid applications every 3 weeks to the trunks of trees. Ambrosia beetles usually attack below the first scaffold branches so you do not need to spray the canopy. Most folks apply permethrin with an airblast sprayer. We have tested a manual sprayer and fold more complete, even coverage. You can read about it in a recent paper (http://ecoipm.files.wordpress.com/2012/02/franksadof2011reprint.pdf). The manual sprayer has two opposing nozzles to quickly cover tree trunk with insecticide. It takes a little longer but uses less insecticide and reduces drift and secondary mite outbreaks.

It’s Still Aphid Season . . .

Last week I reported on rose aphids covering the buds of a rose vine in my neighborhood. This week I poked around campus and found several more aphid species. The first site was spirea aphids. These aphids were coving the new tips of spirea plants at a park in Cary, North Carolina. The result is distorted foliage if they feed on the growing tips too long.

Last week I found some crape myrtle aphid eggs on a tree that still had leaf buds but no leaves. They were shiny black and tucked beneath slivers of papery bark. This week when I went back to find them I only found shriveled black shells. Several days later I found the first crape myrtle aphids of the year. This coincided with the first full grown leaves. Crape myrtle aphids are specialists and only feed on crape myrtle. They occasionally become abundant but are usually subdued by natural enemies.

Finally I found tulip poplar aphids starting to build up on tulip poplar leaves. I watch these every year. For a couple weeks the aphid density increases then you start to see parasitoid mummies and lady bug eggs. For the rest of the summer they stay under control.

Aphids often become abundant this time of year because they are slightly ahead of their predators and parasitoids. However, soon the natural enemies catch up and keep the aphid populations in check. In many cases having some aphids on the plants around your house is good because it attracts predators and parasitoids that will feed on other more damaging pests.

Protecting Pollinators

This time of year many folks are applying systemic neonicotinoid insecticides to their plants and grass. Research has found that these insecticides move into plant nectar and pollen. Through this route they can negatively affect pollinators and especially bees. I reposted a blog post about protecting pollinators from last year (http://ecoipm.com). This provides more detail and links to a review by the Xerces Society about the effect of neonics on pollinators.

Boxwood Leaf Miners Emerging

Last week I saw a lone boxwood leaf miner adult hovering around a bush on campus. This week I went to look for more. I didn't find adults the day I went out but did find pupal casings sticking out of leaves. This indicates adults recently emerged. The maggots pupate in the leaf blister. As the adult emerges the pupal case get caught on the leaf. This holds the leaf in place so the adult can wriggle out. Boxwoods can be treated with a pyrethroid to prevent flies from landing on the bush to lay eggs but watch out for mite outbreaks. Imidacloprid will kill maggots within the leaves but (based on article above) it is best to apply after flowering.

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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 Alert for Week of April 21

ORNAMENTALS AND TURF

From: Steve Frank, Extension Entomologist

Rose Aphids

This week I found a lot of aphids on some rose bushes near my house in Raleigh. I have not yet determined whether they are rose aphids, Macrosiphum rosae, but it doesn't matter a lot to folks managing them. This seems early to have such a large population of aphids but there they are. Aphids can be managed with horticultural soaps or oils or with a number of different insecticides in the aphid fact sheet. One of the most common is imidacloprid but research shows that systemic neonicotinoids like imidacloprid can be harmful to pollinators that ingest pollen and nectar. So consider other options before drenching plants with these insecticides.

More information can be found at http://www.ces.ncsu.edu/depts/ent/notes/O&T/flowers/note38/note38.html.

Oak Eriococcin Scale Active

Oak Eriococcin, Acanthococcus quercus, is not very well known. Not much research has gone into understanding its biology or control. It is in the family Eriococcidae which includes several felt scales including Azalea bark scale. This scale is quite common around Raleigh and is very apparent this time of year. As the name implies its primary hosts are oak trees. I find it primarily on willow oaks along streets. The oaks on Hillsborough Street (near North Carolina State University campus) are literally covered top to bottom. The scale produce cottony white egg masses that are often in the crotches of twigs. Very little efficacy data is available but there are reports that imidacloprid and other treatments for soft scale work for these as well. Even horticultural oil may be an effective treatment this time of year right after egg hatch. More information can be found at http://www.ces.ncsu.edu/depts/ent/notes/O&T/shrubs/note156/note156.html.

Cankerworm Update

I have written about cankerworms already, but this year has been bad and I am getting a lot of calls and e-mails about them. At this point, you can expect the cankerworms to hang around for another week or two then disappear. They have defoliated some trees on campus and covered others with dense webbing. Cankerworms do not create webbed nests the way tent caterpillars and webworms do. The webbing is just a tangle of thousands of threads from which the caterpillars dangle. Above are pictures to assist pest managers or Extension agents with calls or complaints so you can see what folks are experiencing.

More information can be found at http://ecoipm.com/research/cankerworm-project-home/.

       

From: Emma Lookabaugh, Plant Disease and Insect Clinic, and Barbara Shew, Extension Plant Pathologist

Be on the Lookout for Cedar Apple Rust

Most of us who live in the triangle are hoping for rains to wash away the yellow film of pollen coating our cars, houses, and sidewalks. Spring rains also jump start the most bizarre life-stage of cedar apple rust, a common disease that affects apple trees (and crab apples) and eastern red cedar trees.

The cedar apple rust pathogen (Gymnosporangium juniperi-virginianae) requires two hosts and four spore stages to complete its complex life cycle. On cedar trees, the most obvious signs of infection are firm brown galls, which are about the size of a golf ball and are usually found scattered on the tree’s branches and twigs. After a heavy rain, the galls produce striking bright orange gelatinous horns, which are composed of millions of spores called teliospores. In dry periods, the horns can be seen as short spikes covering the galls. If you find a gall with dried horns, cut it out of the tree, place it in a glass of water and watch over the next few hours as the horns expand.

The cycle of wetting and drying can continue several times during the spring, and in each cycle the teliospores germinate and give rise to another spore type, called basidiospores. These basidiospores are forcibly discharged into the air and are wind-blown to nearby apple trees.

Apple leaves and fruit are most likely to be infected when they are wet and temperatures range from 46 to 75° F. Yellow to orange spots are produced on the upper surface of the apple leaves one to two weeks after infection. The spots on leaves may be raised or swollen and infected fruit may be slightly distorted. Small black dots within the lesions signal the production of the next spore type, the pycniospores (also called spermatia). One to two months later, fringed cup-shaped structures (aecia) appear on the underside of the apple leaves and these contain aeciospores, yet another spore type.

The aeciospores are windblown to cedar trees in late summer to early fall, where they germinate and infect to produce galls. The galls produce teliospores in the second year after infection, completing the life cycle. G. juniperi-virginianae survives in the gall tissue for only two years. After its second year, the spore producing year, the pathogen dies in the gall tissue. On apples, the pathogen survives only a few months, just long enough to produce the aeciospores that infect cedar trees.

Cedar apple rust causes only minor damage to cedar trees from twig dieback. Damage to apple is more significant and can result severe defoliation and fruit blemishes. Since this pathogen requires both hosts to complete its life cycle, control can be achieved by eliminating one host from the surrounding area, although oftentimes eradication is not feasible or desirable. Additional control measures include the use of disease-resistant apple cultivars, properly timed fungicide applications on apple, and removal of cedar galls before spring rains.

Check out this cool video of telial horns expanding (Video: Arlene Mendoza-Moran):

http://www.youtube.com/watch?v=-lZ_twBLr3Q&feature=player_embedded#t=0s

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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 Alert for Week of April 14

ORNAMENTALS AND TURF

From: Steve Frank, Extension Entomologist

Ambrosia Beetles

Ambrosia beetle activity has been sporadic this year. Remember those two 70-degree days in January? I had reports of ambrosia beetle attacks on those two days. Since then I have had a few other reports of beetles in traps or occasional attacks. At our research nursery, Raleigh, however, we hadn’t captured any until this week. Then Tuesday the traps filled up and two trees were hit. It seems ambrosia beetles are finally out in Raleigh and we had similar reports from the mountains and foothills. 

Ambrosia beetle management starts with reducing plant stress. In particular we have found that trees with too much water are preferentially attacked. It is easy to overwater this time of year when transpiration and evaporation are low. The next step is preventive applications of permethrin. Apply permethrin to tree trunks and try to avoid spraying the canopy. Our research shows that spraying tree canopies results in spider mite outbreaks later in the year (see the paper here:http://ecoipm.files.wordpress.com/2012/02/franksadof2011reprint.pdf). 

Cankerworms Hatching

Cankerworms were very abundant last spring and we predict the same this year. Cankerworms eggs were laid over the winter and just started hatching in Raleigh last week. You can see the tiny caterpillars if you shake branches or just watch for them dangling below trees. They feed on many hardwood tree species but willow oaks seem to be damaged most heavily. We have written a lot on the biology and management of these critters. See a recent article in American Nurseryman (http://ecoipm.files.wordpress.com/2013/03/an_feb13_planthealth.pdf). You can find information and links to other articles on our dedicated Cankerworm Project webpage (http://ecoipm.com/research/cankerworm-project-home/cankerworm-project/). The important thing to remember is that they only feed for 4 to 6 weeks and only have one generation per year. By the time they get big and start defoliating trees they are about to quit and pupate in the soil until fall. The best management tactic is tree banding in the fall when adults are active. This time of year there is not much to do especially for large trees.

Eastern Tent Caterpillars

Eastern tent caterpillars hatched in the past couple weeks and have already established big nests. The easiest way to deal with tent caterpillars is to prune out the nests. Eastern tent caterpillars make nests in the crotch of trees. (Fall webworms make nests at the end of branches.) So it you can’t remove the nest you can poke it with a pole pruner. This destroys the nest so many caterpillars fall to the ground and others get eaten by birds. Opening the nest also lets parasitoids in to kill the caterpillars. For severe infestations there are some insecticide options. Products containing Bacillus thuringiensis (Bt) are effective against caterpillars. Other active ingredients labeled for caterpillar control include spinosad, Beauveria bassiana, acetamiprid, acephate, azadirachtin, and bifenthrin. Keep in mind that these caterpillars spend most of their time in a water-proof nest so contacting them is difficult. This limits the efficacy of many insecticide applications.

Extension Resources Online

We have many extension resources such as factsheets, articles, pest news, and presentations consolidated as links on my website (http://ecoipm.com). In addition, you can visit the site to read my blog or twitter feeds. You can also sign up to follow my pest alert Twitter feed @OrnaPests and my general ecology and IPM twitter feed @ecoIPM via Twitter or by clicking the ‘Follow’ buttons on my website. @Ornapests provides short timely alerts when new pests become active in the field accompanied by pictures and links to management information. I recently posted “pdf” files of about a dozen articles I have written for industry magazines and a new free book on the management of tree pests in nurseries and landscapes (http://ecoipm.com/extension/extension-resources/).

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

Pest Alert got April 11th 2013

North Carolina Pest Alert for spring 2013

Impatiens downy mildew

From Dr. Kelly Ivors

THIS INFORMATION BELOW WITH EMBEDDED LINKS CAN BE FOUND AT: http://go.ncsu.edu/impatiens_downy_mildew

Impatiens downy mildew was recently identified in a Virginia greenhouse in mid-January 2013 on impatiens cuttings taken from plants originally obtained from a North Carolina greenhouse in December 2012. Based on information from prior years, the 2013 impatiens downy mildew situation in our area is predicted to remain problematic. However, what time of year it shows up in the landscape and the level of downy mildew severity will depend on local weather conditions and how the ‘winds blow’.

For a quick summary of the history, spread, symptoms and risks, check out 

Everything You Need To Know About Impatiens Downy Mildew.

Downy mildew of impatiens is caused by the fungus-like organism Plasmopara obducens. The group of organisms that cause downy mildew diseases are more closely related to the well-known plant pathogens Phytophthora and Pythium than they are to true fungi. This is an important distinction because many of the traditional fungicides used to control fungal diseases of plants do not have efficacy against the downy mildews.  All types of propagated Impatiens walleriana, including double impatiens and mini-impatiens, and any I. walleriana interspecific hybrids, such as Fusion® impatiens, are susceptible to downy mildew; however, all New Guinea impatiens (I. hawkeri) and interspecific hybrids such as SunPatiens® are immune to impatiens downy mildew. No other bedding plants are known hosts of this particular downy mildew, although there are a few other downy mildew species that specifically attack other floriculture plants like coleus and basil.

Given the high plant mortality associated with epidemics of impatiens downy mildew, everyone growing impatiens should be treating with fungicides preventatively, because once it starts it is very difficult, if not impossible, to control. However, fungicide treatments are not recommended for plants in the landscape; instead, all infected impatiens should be pulled from the landscape and destroyed. Fungicides are not always 100% effective at eliminating the disease. Allowing infected plants to remain in the landscape may allow the pathogen to overwinter as resting structures (called oospores), which can start a new epidemic later in the year or in following years if impatiens are replanted in the area. New Guinea impatiens, coleus, begonia, or other available bedding plants are safe to reset in the affected area.  A nice list of planting alternatives to impatiens can be found here.

A number of plant pathologists have been researching this disease to provide science-based information to greenhouse growers, plant retailers, landscapers and home gardeners. A list of resources can be found below:

General information:

Illustrations of symptoms in production and landscape 

Impatiens downy mildew Fact Sheet 

Impatiens downy mildew: a review

Grower information:

Impatiens Downy Mildew Grower Guidelines

Preventive and responsive chemical control programs

A list of fungicides labeled for downy mildew control 

Assessing Risk 

Landscaper / Gardener information:

FAQ's for landscapers 

Impatiens Downy Mildew in the Landscape 

A Practical Approach for Landscaper Gardeners

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

Brown Marmorated Stink Bug

If  you haven't seen the Brown Marmorated Stink Bug this will likely be the year you get a visit from this interesting pest.  Here is a link to an article and video on US Today discussing this pest

New Bug in Town?

In addition consider visiting this website for more information:  BMSB

If you find any life stage of this insect please let us know! 

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

New Insects to Look out for.

As the Spring warms up and plants begin to leaf out, insects start moving from their warm overwintering places or begin to hatch out.  A couple of insects that have been rapidly coming into our area are Kudzu Bugs and Brown Marmorated Stink Bugs.  The stink bugs have a broad host range and are often found on Paulownia ("empress tree"), Ailanthus ("tree of heaven"), and crabapple among others, but at this point in the year (particularly here western NC) those host plants have little foliage and cooler weather has kept the bug activity down. And so, a lot of this current activity is simply a response to the warmer temperature and you'll see the insects on non-host sites, such as house siding, cars, etc.  Keep a look out for this pest though as the nymphs have a wide range of possible food sources and could produce some damage as the summer comes on us.  Controlling them should be rather simple, particularly in the earlier nymph stages.

Kudzu bugs will be aggregating on almost anything and so you will see them on wisteria and other plants (even if there isn't much foliage), houses, early-planted beans in people's gardens, etc. But even on plants with foliage the insects will simply be hanging out rather than feeding.   Kudzu bugs probably will not cause that much damage to ornamental plants but monitoring them is still a good idea.  Last year they seemed to come out in enough numbers to alarm many people.


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

Green Team Quarterly

The Green Team Quarterly has been posted for the Spring of 2013.  Visit the on-line version at: Green Team Quarterly.   Remember if you have someone who wants to become a Certified Plant Professional or Landscape Contractor the CPP Short Course Registration form is now posted at:  http://buncombe.ces.ncsu.edu/certified-plant-professional-short-course-2013/.  It is time to get those registrations in!




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