Posts by Jean Williams-Woodward

The April Update includes:

• March Plant Disease Clinic Report
• Table of plant disease samples diagnosed a year ago in April 2012
• Eastern red cedar rusts
• Bulb mites and spot anthracnose samples
• Watch out for downy mildews on ornamental plants
• Fungicide spray guide for Spring-planted peppers
• Wheat foliar disease update
• Turfgrass disease update
• Winter weather in March could affect row crop diseases
• Bacterial leaf scorch on blueberry research results
• Corrected contact information

See the entire report HERE

By Ansuya Jogi and Jean Williams‐Woodward

The tables in the link below consist of the commercial and homeowner samples submitted to the plant disease clinics in Athens and Tifton for February 2013 (Table 1) and one year ago in March 2012 (Table 2). Sample numbers were still low in February, but this will soon change! Much of the symptoms we saw on samples were due to environmental stress/injury. However, root and crown diseases caused by Phytophthora, Thielaviopsis basicola, and Rhizoctonia continue to be identified. Also, with the cooler, humid, wet weather, the fungus, Botrytis, will continue to cause problems in the field and in greenhouses, particularly on freeze damaged tissues. Looking ahead through March, based upon samples diagnosed a year ago, we will likely see an increase in turf samples and problems, as well as rust and Sclerotinia diseases starting to show up. I would suspect too that downy mildew diseases will also become prevalent on some crops, particularly on ornamentals in nurseries.

http://plantpath.caes.uga.edu/extension/documents/ExtensionPlantPathologyUpdate-March2013_000.pdf 

Jean Williams-Woodward, University of Georgia Extension Plant Pathologist, will present common winter annual flower diseases, what to watch for, and how to control them. This Webinar is free to all Landscape Contractors and Extension Professionals.

A complete schedule and archive of Landscape Professional webinars may be found at http://ugaurbanag.com/webinars

These webinars are easily viewed with a smart phone or iPad so you can be on the run.

” Bacterial spots and blights on ornamental plants “  will be presented by
Dr. Jean Williams-Woodward Warmer temperatures tends to increase bacterial
diseases on plants. Leaf spots, blights, and wilts are becoming more common
within nurseries and greenhouses. This webinar will cover what to look for
to identify and manage bacterial plant diseases.

Here’s how to participate in the webinar:

Before the webinar, click on the link below.
http://go.ncsu.edu/bacterial_spots_and_blights

You will be able to enter the session starting at 10 am EDT on the day it
occurs (for trouble shooting if necessary), but the actual webinar will not
start until 11 am EDT.

All that you need is an up-to-date browser and internet connection (and no
firewalls!). We will run the webinar off of NC State’s ELLUMINATE site
license, so you don’t need a copy of the program yourself. In order to make
test that your system requirements are acceptable, visit the Configuration
Room linked on http://go.ncsu.edu/elluminate_config

In addition, Elluminate tips can be found at the link below.
http://collaborate.extension.org/wiki/Elluminate_Tips

In response to this disease outbreak, it may be advisable for growers and landscapers to limit impatiens orders for spring sales and use begonias or New Guinea impatiens as replacement plants as these are not susceptible to infection. If plugs are coming from Florida growers, supplies of impatiens may be limited. We don’t know how the disease will progress during our hot, summer months; however, past experience with this disease in a few states suggests that the pathogen stops producing spores and infecting plants during hot weather. One of the main concerns for growers is that although they may be able to reduce infection and symptom development within their operation through preventive fungicide applications, once these plants go out into the landscape, the disease may cause severe losses for their customers in the spring and fall as fungicide use is often not continued in landscapes. Impatiens downy mildew infection can be reduced through fungicide drenches (28-day interval) or sprays (7-day interval) of Subdue MAXX (mefenoxam), Adorn (fluopicolide), Vital (potassium phosphite), Protect T/O (mancozeb), Pageant (pyraclostrobin + boscalid), Disarm (fluoxastrobin), Segway (cyazofamid), Stature SC (dimethomorph), FenStop (fenamidone) and Heritage (azoxystrobin) plus Capsil as a surfactant. Aliette (fosetyl-Al) has not provided control of this disease in several trials. Fungicide resistance development is a real concern for downy mildew diseases, so rotate fungicides making no more than two consecutive applications of the same fungicide or a fungicide with the same mode of action (with the same FRAC code).

Since most downy mildew diseases are blown northward from southern regions during storms, it may be only a matter of time before this disease shows up in Georgia and other southeastern states. If you have questions, please contact me at jwoodwar@uga.edu.