{The Plant Disease Information Office}

The Plant Disease Information Office (PDIO) is part of the Department of Plant Pathology and Ecology of The Connecticut Agricultural Experiment Station.  Dr. Sharon M. Douglas, Plant Pathologist and Head of this Department (Phone 203.974.8496, Email, oversees these service efforts.  The PDIO is a full-service plant disease diagnostic laboratory that assists all Connecticut stakeholders, including homeowners and professionals.  Plant samples are diagnosed utilizing molecular, serological, biochemical, and traditional diagnostic methods. The PDIO also assists with inquiries about plants, plant identification, and plant health.

A new color brochure about the Department of Plant Pathology and Ecology is available (PDF format*).

Dr. Yonghao Li, plant pathologist, ( is responsible for the office, with assistance from Ms. Lindsay Patrick, technician (

We've moved! 

Please come and visit the PDIO in the newly renovated Jenkins-Waggoner Laboratory. The PDIO is now conveniently located in Room A102 of Jenkins-Waggoner Laboratory and is fully accessible.  Office hours are Monday-Friday, 8:30 a.m.- 4:30 p.m.  If you have any questions, please call 203.974.8601 or 203.974.8606.

The Experiment Station's PDIO is a member of the National Plant Diagnostics Network (NPDN)

Welcome New PDIO Diagnostician

The PDIO is pleased to welcome our newest staff member, Lindsay A. Patrick.  Lindsay started in her position as an agricultural technician / diagnostician last month and will be investigating new diagnostic methods for plant problems common to Connecticut.  She is assisting with seed testing for purity and germination and truth in labeling as part of the Station's role as the official seed testing laboratory for the State of Connecticut. Her other responsibilities include assisting with organizing protocols and documentation in advance of future accreditation by the National Plant Diagnostic Network.

Lindsay grew up in Michigan and recently earned her MS degree at Purdue University working on  the effects of grafting various ash species to increase resistance to the emerald ash borer.  Upon graduation in May 2014, Lindsay worked with Bartlett Tree Experts (Simsbury office) as a plant health care specialist prior to joining CAES.

Please help us welcome Lindsay Patrick to the PDIO team.  Feel free to stop in, call, or email Lindsay to say hello.

{Lindsay Patrick CAES PDIO}

Lindsay Patrick


{Boxwood blight leaf spots}

July 2015
New Fact Sheet
Using Mineral Nutrition to Suppress Plant Diseases

This new fact sheet reviews one of the fundamental strategies for maintaining plant health and suppressing plant diseases by managing nutrition.  Proper nutrition can often influence the fine line between host susceptibility and resistance.  Examples of specific diseases and elements are covered in the fact sheet on Using Mineral Nutrition to Suppress Plant Diseases (PDF*format) by Dr. Wade Elmer.

June 2015
New Fact Sheet
Fire Blight Management During Bloom

Fire blight, caused by the bacterial pathogen Erwinia amylovora, is an important and potentially devastating disease of apple and pear.  Bloom time is a very important stage for fire blight infection because the natural openings in the flowers provide the fire blight bacteria an easy entry into the tree. This fact sheets discusses how to understand management of this disease from the standpoint of disease biology.  This new fact sheet on Fire Blight Management During Bloom (PDF*format) by Dr. Quan Zeng is now available.

May 2015

New Fact Sheet

Rhododendron Tissue Proliferation

Rhododendron tissue proliferation is a condition that causes tumor-like growths and shoots to form at the base of many cultivars of rhododendron.  Early symptoms are often confused with crown gall, a disease caused by the bacterium Agrobacterium tumefaciens. A new fact sheet on Rhododendron Tissue Proliferation (PDF*format) by Dr. Lindsay R. Triplett is now available that describes how to handle this condition.

April 2015
Updated and Revised Fact Sheets Available
Downy Mildew of Basil

Last year many gardeners were disappointed with their basil crops--plants collapsed early in the season, often before they could be harvested.  Widespread outbreaks of downy mildew of basil was the likely culprit.  A new fact sheet on Downy Mildew of Basil (PDF*format) by Dr. Yonghao Li is now available that discussed how to recognize and manage this destructive disease.

Dooks Needle Blight (Formerly Canavirgella Needlecast) of White Pine

Many white pine throughout the region have been showing a yellow and brown discoloration of current-season needles.  Although several needlecasts have been associated with this damage, Canvirgella needlecast was reported as a key component.  Recently, however, the identity of Canavirgella banfieldii has been questioned, since there is evidence that it is really Lophophacidium dooksii, the fungus associated with Dooks needle blight—the two names are thought to be synonyms for the same fungal species Dooks Needle Blight (Formerly Canavirgella Needlecast) of White Pine  (PDF format*) by Dr. Sharon M. Douglas is now available. 

Excess Water Problems on Woody Ornamentals

As the snow is melting, localized flooding may occur. Excess water and poorly drained soils can  present serious problems for many woody ornamentals that may result in plant decline and death as well as uprooting of trees and large shrubs.  Learn how to recognize and manage water issues in the newly updated fact sheet Excess Water Problems of Woody Ornamentals (PDF format*) by Dr. Sharon M. Douglas.

Pruning- An Introduction to Why, How, and When

Pruning is probably one of the least understood and most daunting landscape maintenance practices for most homeowners.  Many people aren't sure what to do or when to do it.  This updated fact sheet reviews the basics of pruning for shrubs and small ornamental trees.  Learn more about pruning with Pruning: An Introduction to Why, How, and When (PDF format*) by Dr. Sharon M. Douglas.

March 2015

Downy Mildew of Impatiens and Seiridium Canker of Leyland Cypress

(New Fact Sheets Available)

After the widespread outbreaks of downy mildew of impatiens in 2011, it is important for growers, landscapers, and homeowners to be able to recognize this potentially devastating disease. A new fact sheet that describes the symptoms and management of this disease Downy  Mildew of Impatiens (273 kb, 2 pages, PDF format*) by Dr, Yonghao Li is now available. 

As Leyland cypress has increased in popularity as a landscape plant, a fungal disease called Seiridium canker is becoming more prevalent in these plantings. Learn how to recognize and manage this disease in the new fact sheet Seiridium Canker of Leyland Cypress (PDF format*) by Dr. Yonghao Li. 

February 2015

Did you have fire blight on apples, crabapples, or pears last year?

(New Fact Sheet Available)

Outbreaks of fire blight, caused by the bacterium Erwinia amylovora, were observed in many orchards and some landscapes in throughout Connecticut and other New England states last year.  If you had a problem, it might be prudent to inspect your trees now and take some proactive steps towards managing this potentially devastating disease before the growing season.  A new fact sheet Winter and Early-Season Fire Blight Management (PDF format*) by Dr. Quan Zeng is now available. 

  --For Children--

Coloring and Activity Books

The Experiment Station's Coloring and Activity Books for Kids are now available online in the Publications section of this PDIO website.  These books highlight many topics of plants and agriculture in Connecticut and the activities of Station scientists.  The newest edition, Coloring and Activity Book for Kids III (2011) (PDF format*), is now available.  It was edited and prepared by Dr. Sharon M. Douglas.


--Archived Disease Alerts--

Disease Alert- Begin to Scout for Downy Mildew of Impatiens (July 2013)

Disease Alert- Late Blight Reported in MA: Scout for Late Blight of Tomato and Potato (July 2013)

Disease Alert- Downy Mildew of Impatiens (August 2012)

Disease Alert- Late Blight of Tomato and Potato (June 2012)



Presentation from the CTPA Summer Meeting 2013 by Bob Marra titled Tropical Storms, Hurricanes, and "Superstorms": Impacts and Influence on Tree Diseases  (PDF format*).


Newly revised and updated presentation by Sandy Anagnostakis titled Growing Chestnuts in the Northeast (PDF format*).

Some previously posted presentations from meetings are archived and can be accessed by clicking here.


2 July 2015 (updated)

*NOTE: Some of these documents are provided in Adobe® Acrobat™ (.pdf) format. If you do not have Adobe® Acrobat™ Reader to view and/or  print your these documents,  you will need to download the Adobe® Acrobat™ Reader. To get a free copy of the software, click the "Get Acrobat" image. 
{Adobe Acrobat Reader}



Content Last Modified on 7/2/2015 10:58:24 AM