Fusiform Rust: What's that orange stuff on my pine tree?

Just last week, I noticed the galls on the pine trees in my back yard started bursting open with the bright orange spores of fusiform rust. Fusiform rust is a damaging disease in landscapes and forests of the South. The most obvious symptom is spindle-shaped swellings or galls on the branches or trunks of pine trees.

Fusiform rust is caused by the fungus Cronartium quorum f. sp. fusiforme. Like many rust species, this fungus produces five different spore types and completes its life cycle on two different hosts: pine and oak.

During the spring, the fungus produces bright orange spores like the ones I observed on the galls. Typically, these spores are produced from late March to mid-April. Wind-blown spores infect newly formed leaves of several oak species, especially water, willow, and laurel oaks. Symptoms on oak are not conspicuous and usually the tree is not harmed. The fungus produces a different type of orange spore on the under-surface of oak leaves from late April through the middle of June. These spores are then wind-blown to nearby pines where they create new infections, causing new galls and continuing the cycle.

Pine trees are highly susceptible to Fusiform rust when young and infections that occur within the first 5 years of growth usually result in death. Later, main stem cankers can girdle and kill the tree or reduce its value. Stems with cankers are weak and susceptible to wind and ice breakage, and galls easily catch fire and stay afire. Secondary infections by the pitch canker fungus (Fusarium moniliforme var. subglutinans), black turpentine beetles (Dendrodoconus frontalis) and coneworms (Dioryctria spp.) aggravate the tree’s weakened condition, causing further damage.

Over the years, fusiform rust has become an increasing problem, particularly in pine plantations. Loblolly and slash pines are the most susceptible tree species. Longleaf is fairly resistant and shortleaf is highly resistant.

Management options include spraying fungicides, planting longleaf or shortleaf pines in areas with histories of severe rust infections, pruning branches with rust galls less than 15 inches from the stem, eliminating nearby oak hosts, and using rust-resistant clones.

For more information click here,

Red Bay Ambrosia Beetle Found in North Carolina!

The North Carolina State University Plant Disease and Insect Clinic, in communication with U.S. Department of Agriculture and North Carolina Department of Agriculture & Consumer Services, has corroborated the presence of red bay ambrosia beetle in North Carolina. This tiny exotic beetle was first detected in North Carolina this March, in Bladen County, by the North Carolina Forest Service.

Red bay ambrosia beetle transmits laurel wilt pathogen.
(Image Michael C. Thomas, Bugwood)

The red bay ambrosia beetle, Xyleborus glabratus, and the fungus Raffaelea lauricola, together constitute an insect/disease threat.

The beetle transmits the fungus which causes the disease known as laurel wilt. The combination is generally fatal to red bay, which is an important maritime forest species and is also sometimes found in the landscape. The decline of red bay may have secondary implications for some animals and other plant species.

Other plants in the laurel family, including sassafras, are also susceptible to the fungus. This disease complex a serious threat to the avocado industry in Florida.

Symptoms of laurel wilt.
(Images James Johnson, Bugwood)

For more information, click here

More information on Laurel Wilt will be presented in tomorrow's Plants, Pests, and Pathogens elluminate session.

Herbicide Injury to Tomatoes

"Classic" Glyphosate Symptom

Recently, the clinic has received several tomato plants with symptoms of herbicide damage. Glyphosate (found in products like Roundup) causes very distinctive yellowing symptoms at the base of tomato leaflets.  Broad-leaf weed killers (2,4-D type herbicides) cause stunted and deformed new growth, and whipping and curling of the leaves.  

2-4 D Type Injury 

Tomatoes are very sensitive to herbicide injury and damage can be severe.  In extreme cases, simply touching tomato plants with herbicide-contaminated hands or clothing can cause injury. 

Spray drift is an important source of herbicide damage. Sometimes symptoms appear in a gradient pattern, with plants closest to source being more affected than those further away. 

Be careful to prevent herbicide drift into home gardens, farms, or greenhouses where tomatoes are growing. To reduce the chances of spray drift, do not apply herbicides near these areas on windy days.  

Glyphosate Drift in Greenhouse

Some herbicides are formulated to provide season-long protection against weeds. Planting sensitive crops too soon after using one of these herbicides can cause injury. Check the product label to see when it is safe to replant following herbicide application.

Glyphosate Injury

Sometimes farmers and home gardeners report problems in vegetables and flowers after applying hay, manure, grass clippings, compost, or other amendments to soil.   Symptoms include poor seed germination, twisted, cupped, and elongated leaves, and misshapen fruit. Young plants may die and yields may be reduced in mature plants.  This damage can be traced to herbicide carryover in the soil amendment.  For more information on herbicide carryover in soil amendments, click here.

Be on the Lookout for Camellia Petal Blight

Petal blight is very common on camellias in the spring. It is caused by the fungus Ciborinia camelliae. Although petal blight can affect both japonica and sasanqua camellias, it is usually seen in early spring when japonica camellias are in bloom. Disease development is favored by frequent rain showers, high humidity, and mild temperatures during bloom.

The disease is first seen as brown spot on the expanding flower petals. In the early stages of disease, veins within the spots appear darker than the surrounding tissue, giving some blooms a distinctive netted appearance.

Camellia petal blight: Note the distinct netted appearance

The spots quickly increase in size and often extend into the base of the flower, causing the entire flower to fall to the ground. A ring of white fungal growth may be visible where the blossom was attached to its base.

Camellia petal blight: Fallen blossoms

Camellia petal blight: Note the white ring of fungal growth at the base of the flower (top of image). Later, very large sclerotia are produced at the flower base

The blighted petals are dry or leathery but do not crumble when handled. Petal blight can be confused with cold injury, but cold injury is usually found on the outer petals, which become dry and crumbly and do not fall from the plant. Flowers from the same plant can have petal blight and cold injury.

Several weeks after the petals fall to the ground, hard black fungal structures similar in size to a chickpea may be found at the base of the flower (seen above, lower right). These sclerotia can persist in the soil for several years. Under favorable conditions (cool weather followed by warm, wet weather), the sclerotia germinate to produce tiny mushroom-like structures. The “mushrooms” produce airborne spores that land on nearby camellia flowers, starting a new cycle of disease.

Camellia petal blight: Mushroom-like structures produced from sclerotia germination

How to Control Petal Blight

Fungicide sprays can be used to control petal blight, but sanitation is the key to controlling this disease in the landscape. Because sclerotia produced in diseased flowers are the source of future infections, the best way control petal blight disease is to remove all fallen flowers and debris from the ground around camellia plants. The sclerotia are too large and hard to be completely destroyed by composting, so infested debris should be disposed of completely. Remove old mulch each spring and lay a layer of fresh bark or pine straw around the base of each plant. The mulch will interfere with the spread of spores from previous years’ infections.

** Be sure not to add more than 1inch of mulch. Burying the root system by adding 2 or more inches of mulch may kill the plant!

A milestone

This morning, Friday 3/11/11, the ten thousandth sample was entered into the PDIC database, which went online in January 2008.

Plants, Pests, and Pathogens Webinar

Greetings,

We hope you can join us for Plants, Pests and Pathogens, Tuesday 2/22/2011 at 10am.

You can participate in this two-hour training opportunity for Master Gardeners and Horticulture Agents via your computer, or you can go to one the of downlink sites. To participate from your computer:

• Log In by 9:30 am. Include your county with your name and leave the password field blank
• Take a few minutes ahead of time to visit the page on How to Use Elluminate. Check to be sure that you have downloaded the free software required to run the program.  There are one page reference guides and tutorials available.

In order to minimize interference, please keep your microphone turned off, except when you are speaking to the group.


Schedule for February 22 Session:

• 10:05 am- Regional Update, Coastal Plains: Bob Filburn, Edgecombe County Horticulture, Apiculture, Local Foods Initiative, and Forestry-- Green Thumbs on Wheels
• 10:10 am-Regional Update, Piedmont: David Goforth, Carbarrus County, Horticulture
• 10:15 am- Regional Update, Mountain/Foothills: Cliff Ruth, Commerical Horticulture, Henderson and Transylvania Counties-- Weed Scouting Class
• 10:20 am- Featured Speaker: Hannah Burrack, Assistant Professor of Entomology and Extension Specialist, tobacco and Small Fruits
• 11:00 am- Entomology: David Stephan, NCSU PDIC, Insect Identification Specialist, 40 years experience
• 11:35 am- Current Issues in Plant Pathology: Mike Munster, PDIC, Plant Pathologist and Diagnostician of Commercial Ornamentals 

Prime Weather for Paper Wasps

You aren't the only one heading outside to enjoy the beautiful weather... female paper wasps have started leaving their winter homes and may soon be seen swarming yours!

Paper wasps (Polistes spp.) eat a lot of insects and are usually considered beneficial to the landscape.  They are best known for their open, grey paper nests built under an open porch ceiling, window sill, or any type of overhang.  During their nesting phases, paper wasps can be defensive and are likely to sting you if you disturb their nests.  

During the cool/ cold times of the year, when their are no nests or young to protect, paper wasps show types of swarming behavior.  In the fall, this behavior is connected with mating.  Male wasps look for the best place to "hang out" and attract the females.  Dozens or even hundreds might be seen around the upper stories of buildings and other tall towers.  Males locate a good perch, camp out, and release odors (pheromones) to attract the pretty female wasps.  Some time after mating, the males die and the females seek a shelter for winter. 

During winter and early spring, on any warm day (like the one's we've been seeing this week!), these wasps become active.  If their shelter is inside a wall, chimney, or vent, they may follow the light into the inside of a structure rather than moving outside. The only risk is unknowingly coming into contact with the wasp and being stung. The future queens become active on warm days and start flying around, however they are not particularly defensive and are unlikely to attack.  This flying behavior disappears at the end of the day when temperatures drop and the wasps resettle.  

The best management and control of these wasps indoors is a rolled-up newspaper.  Aerosol pesticides work, but they cost money and aren't particularly necessary if you are able to whack the wasps with a paper or fly swatter.  

For more information on Paper Wasps click the link below:

Paper Wasp Information

Special Thanks to Steve Bambara and Michael Waldvogel for this great Insect Note!

Elluminate Training Sessions: URL Links and Instructions

Below are the links for the Elluminate (interactive webinar) sessions on Plant Disease Diagnostic Training. 

February16:
http://elluminate.wolfware.ncsu.edu:80/join_meeting.html?meetingId=1261500568610
February 23:
http://elluminate.wolfware.ncsu.edu:80/join_meeting.html?meetingId=1261500568609
March 2:
http://elluminate.wolfware.ncsu.edu:80/join_meeting.html?meetingId=1261500568608
March 9:
http://elluminate.wolfware.ncsu.edu:80/join_meeting.html?meetingId=1261500568607

If you have never used Elluminate before, follow these instructions:

Our Elluminate session Plant Disease Diagnostic Training, is scheduled for the above dates. You can connect to the session by clicking the above links to the sessions.

Before connecting to Elluminate for the first time, make sure to complete the Configuration setup. You MUST do this at least 24 hours ahead of time. 

Please use the same location and equipment that you will use when you attend the actual Elluminate session(s) to complete the following steps:

1. Go to http://www.elluminate.com/support
2. Make sure Step 1 shows a checkmark or says that you have Java installed. If you do not see a checkmark, follow the instructions to obtain the latest version of Java.
3. Enter the Configuration Room as outlined in Step 2. Follow the directions in the Configuration Room to test your audio setup.

If you have ANY PROBLEMS configuring Elluminate, call 866-388-8674, option 2. Elluminate Live! support is available 24 hours day, 7 days a week.

To join the session:
1. Go to the Elluminate meeting URL (links above).
2. Under section 2, "User Authentication", select "Guest." 
3. Type in your email address. 
4. Type in your name. 
5. Type in the session password if prompted. 
6. Click "Log In." 

If you have any problems logging in to the session or hearing the audio, call 866-388-8674, option 2.