Skip to Content

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

New IPM Video from UF & UGA

A variety of sustainable pest management strategies are available for nurseries ranging from simple items requiring little investment to major infrastructural changes. This video presents an overview of IPM including sanitation, irrigation and systems approaches to sustainable pest management. More information is available on the project website: http://site.caes.uga.edu/snpp/

To watch the video, click HERE!

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: http://plantpath.caes.uga.edu/extension/ExtensionPlantPathologyUpdates.html

Cicadas in Nurseries and Landscapes

Posted on June 7, 2013 by ecoIPM.com blog visit us for more nursery and landscape IPM information. Follow us on Twitter @OrnaPests. 

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

Oviposition scar. Photo: Tim Tigner, Virginia Department of Forestry, Bugwood.org

Oviposition scar. Photo: Tim Tigner, Virginia Department of Forestry, Bugwood.org

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.  (read the full publication) Females detect the insecticide with their ovipositor so treated trees have fewer scars and the scars are much shorter.  Thus branches do not

Flagging branches. Photo: Linda Haugen, USDA Forest Service, Bugwood.org

Flagging branches. Photo: Linda Haugen, USDA Forest Service, Bugwood.org

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 (read the full publication). 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.

 

Daylily leaf miner is a new pest in Southeast

Posted on June 4, 2013 on http://ecoipm.com.  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.

Managing Roots in the Nursery for Optimal Production and Landscape Performance

In 2011 a new nursery production conference was held on the campus of Kansas State University. NurseryWorks is now an award-winning educational meeting and presentations from the inaugural event are archived and available for  free at www.ksu.edu/nurseryworks. Feel free to peruse the site while we periodically post the archived presentations here.

Managing Roots in the Nursery for Optimal Production and Landscape Performance
Ed Gilman, Professor of Urban Trees & Landscape Plants, University of Florida, Gainesville

Dr. Gillman showed us how to produce a strong root system in the nursery using the correct liner trays, containers, and field techniques using examples from across the continent. There are brand new methods to eliminate root defects in containers and proven field production strategies that ensure good roots. He demonstrated how to create a root flare at the surface instead of 8 inches below the surface and how to set up a test so you can show others. We will thoroughly dissect root systems and show you how they grow in nature compared to in the nursery and landscape. The differences will surprise you and are important to understand! You will come away knowing how to improve root systems on trees of any age. You may be surprised at the amount of new research on this topic, as well as the experience of some professionals treating defects.

Topics covered include: what root attributes lead to stable trees, how trees grow in nature, growing quality root systems in container and field nurseries, how roots grow in urban landscapes, recognizing root defects, prescribing treatments for root defects, root management at planting, improving health of established trees with root pruning, root regeneration capacity, increasing anchorage with root ball shaving, and more.

K-State Nursery Works Ed Gilman
Ed Gilman Handouts
(Another 4 handouts can be found here.)

 

Dr. Gilman, University of Florida, has a 50% research: 50% extension teaching assignment and teaches an arboriculture class. He works with arborists, consultants, landscape contractors, tree nursery operators, urban foresters, planners, landscape architects and others engaged in tree selection, growing, planting and management issues. Research includes irrigation, fertilization, roots, and other tree transplant and after-care techniques and a recent focus on tree response to pruning.
http://hort.ufl.edu/people/gillman.shtml

Turbocharged Diesel Engines and Trees?

Check out these videos from Dr. Ed Gillman (University of Florida) testing the effect of pruning on trees subjected to hurricane force winds. Cool research!

Effect of Hurricane-Force Winds on Landscape Trees–Crown Thinning

Effect of Hurricane-Force Winds on Landscape Trees–Crown Reduction Pruning

Effect of Hurricane-Force Winds on Landscape Trees–No Pruning

 

Dr. Gilman, University of Florida, has a 50% research: 50% extension teaching assignment and teaches an arboriculture class. He works with arborists, consultants, landscape contractors, tree nursery operators, urban foresters, planners, landscape architects and others engaged in tree selection, growing, planting and management issues. Research includes irrigation, fertilization, roots, and other tree transplant and after-care techniques and a recent focus on tree response to pruning.
http://hort.ufl.edu/people/gillman.shtml

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

Sustainable Nursery Irrigation Management Series: Part 3- Strategies to Manage Nursery Runoff

Extension publication, “W 278: Part I. Water Use in Nursery Production,” discussed the importance of and competition for water use in nursery production.
“W 279: Part II. Strategies to Increase Efficiency” covered techniques that growers can use to refine scheduling (volume and timing) and delivery of irrigation water.  This final publication in the series discusses the significance and causes of nursery irrigation runoff and offers strategies to manage runoff.
As discussed in Part I of this series, irrigation can contribute to nursery runoff. While growers generally aim to apply 1 inch of water per day, field studies show that  growers actually apply as little as 0.3 and as much as 1.3 inches per day. The greater the volume of water applied, the greater the potential for runoff. Runoff, or more  precisely, surface runoff, is defined as water moving over the surface of saturated soil. Runoff can cause erosion and carry pathogens and pollutants, such as pesticides, petroleum products, soil, fecal contaminants and nutrients that may contaminate ground and surface water. Agricultural runoff and its link to eutrophication in surface  waters led to legislative action affecting agriculture producers in recent years, including the Neuse River watershed in North Carolina and the Chesapeake Bay.

Sustainable Nursery Irrigation Management Series: Part 2- Strategies to Increase Crop Irrigation Efficiency

Nursery irrigation management is a major concern for many nursery producers, especially container producers. Extension publication, “W 278: Part I. Water Use in  Nursery Production,” discussed competition for water and gave a general overview of water use in nurseries. Part II discusses strategies to increase irrigation efficiency. Because irrigation is so critical to container production and most of the water associated with nursery production is applied to container plants, strategies are discussed  largely in the context of container production.
Growers must make many irrigation management decisions on a daily basis, including when to irrigate, how much water to apply, which plants to irrigate and how to  maximize efficiency. They also must plan for and manage water supplies in order to meet local and state water regulations (Figure 1). Increasingly, competition for water  resources is affecting how these decisions are made.