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The July UGA Extension Plant Pathology Update

The July Extension Plant Pathology Update is now available: HERE

The July update contains information on:
  • Plant Disease Clinic Report for June 2013
  • Diagnoses made in July 2013
  • Cucurbit Diseases in the Home Garden
  • Row Crops: Rains Continue to Drive Concerns for Disease Management
  • Assessing Risk to Target Spot on Cotton in Georgia
  • Dodder management in Blueberries
  • Turfgrass Disease Update: Gray leaf spot and Rust
  • Mushrooms are everywhere
  • Wood decay and falling trees are of great concern

June Extension Plant Pathology Update – University of Georgia

The June update includes:
  • May 2013 Plant Disease Clinic report
  • Table of sample diagnoses from a year ago – June 2012
  • Tomato diseases in home gardens
  • Ornamental Fungicides Efficacy Table online
  • 2013 Vegetable Disease Spray Guides and Efficacy Tables
  • Gummy stem blight on watermelon advisory
  • Turfgrass disease update (Brown patch, Pythium blight)
  • Small grains disease summary for 2012-2013 growing season
  • Recent rainfall could impact disease management in row crops
  • Slime molds in landscapes
  • Time to protect against root pathogens in ornamental plant production

You can download the report HERE.

Past Extension Pathology Updates are archived here:

Daylily leaf miner is a new pest in Southeast

Posted on June 4, 2013 on  Visit us for more nursery and landscape IPM information. Follow us on Twitter @OrnaPests. 

IMAG1880The 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.

Cottony maple leaf scale eggs hatching

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. For more pest updates follow @OrnaPests on Twitter or keep an eye on the blog from North Carolina State University.

Looking up at the bottom of red maple leaves notice the many white cottony egg masses. Photo: S.D. Frank

Looking up at the bottom of red maple leaves notice the many white cottony egg masses. Photo: S.D. Frank 


Cottony maple leaf scale ovisac. Photo: S.D. Frank

Cottony maple leaf scale ovisac. Photo: S.D. Frank

The UGA Extension Plant Pathology Update for May

It contains:
  • April 2013 Plant Disease Clinic Report
  • A look ahead for what you might expect to see based upon samples we diagnosed a year ago in May 2012
And, updates on:
  • Pseudomonas syringae leaf spot on watermelons
  • Fusarium wilt of watermelon
  • What’s the orange goo growing on tree stumps?
  • Rose Rosette Virus
  • Impatiens downy mildew
  • Wet, cool weather has importance for early-season disease management (row crops)
  • Wheat Diseases: Loose Smut, Sooty Mold, and Head Scab
  • Turfgrass Diseases: Large Patch, Dollar Spot, and Spring Dead Spot

April edition of the UGA Extension Plant Pathology Update

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

Plant Disease Clinic Report for February 2013

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. 

Evaluation of fungicides for the prevention of boxwood blight, 2012.

K. L. Ivors, L. W. Lacey, and M. Ganci

Dept. Plant Pathology, North Carolina State Univ.

455 Research Drive, Mills River, NC 28759

This trial evaluated the efficacy of several commercially available fungicides for preventive activity against boxwood blight caused by Cylindrocladium buxicola. Treatments were arranged in a randomized complete block design consisting of four replications of six 1-gal English boxwood plants per treatment on a container pad at the Mountain Horticultural Crops Research Station in Mills River, NC. Treatments were applied as foliar sprays until runoff with a CO2-pressurized backpack sprayer equipped with a handheld boom and a single, hollow-cone nozzle (TXVS-26) delivering 50-60 psi. Treatments were applied on 13 Sep, 28 Sep, and 13 Oct. Inoculum was prepared by flooding Petri-dishes of 10 day cultures of the pathogen growing on PDA. Plants were spray inoculated with 5,000 spores per ml until runoff one day post treatment on 14 Sep, and again on 30 Sep, two days after the second fungicide treatment with 8,000 spores per ml until run-off. Disease assessments were conducted on 1, 16 and 26 Oct. Percent leaf area diseased was recorded using the standard Horsfall-Barratt scale. Disease pressure was not high enough to evaluate percent leaf drop or percent stem streaking. AUDPC for percent leaf area diseased across the entire timeframe of the trial was calculated. Air temperatures during the trial was suboptimal for high rates of infection with average daily high and low temperatures of 77.7 and 55.4°F for Sept; and 66.3 and 43.5°F for Oct.

For the entire article – click here.

Regulatory Plant Issues for Nurseries

Regulatory Plant Issues: What You Must Do to Sell, Import or Export Live Plants from the State of Kansas
Jeff Vogel, Kansas Department of Agriculture

How do you stay up to date with plant quarantines, emerging pest threats and noxious weed lists? It can be very difficult to keep track of importing/exporting issues as well as other live plant sales concerns. Learn the most important aspects of regulatory plant issues from the state perspective.


Jeff is the Program Manager for the Plant Protection and Weed Control Program for the Kansas Department of Agriculture. His office works to ensure the health of the state’s native and cultivated plants by excluding or controlling destructive pests, diseases and weeds. His staff examines and analyzes pest conditions in crop fields, rangelands, greenhouses and nurseries.

“Bringing Nature Home”, sponsored by the Georgia Exotic Pest Plant Council

Do you care about protecting our native plant habitats from invasive plants? How can you tell which plants are invasive? Do you want to know how you can help? First step is to come to the Georgia Exotic Pest Plant Council Annual Conference on November 8th.

The GA-EPPC, Georgia Exotic Pest Plant Council, is having its Annual Meeting and Conference on Thursday, November 8th, 2012, from 9am to 4pm. The conference will be held at Stuckey Conference Center, UGA 1109 Experiment Street Griffin, Georgia.

GA-EPPC’s goals are to focus attention on the adverse effects invasive plants have on the diversity of Georgia’s native plants and animals; the use of invasive plant management to prevent habitat loss; the socioeconomic impacts of these plants; changes in the seriousness of the different invasive plants over time and the need to exchange information to help land owners and managers set priorities for invasive plant management.

For more information please visit