Category Archives: Research

Activity in the TPDDL that include or require some research activity

Student Worker (Oak) Branches Out

Written by Michael Giedraitis – TPDDL Student Worker; Edited by Hannah Ayala – Extension Assistant Background It was an exciting summer and fall at the Texas Plant Disease Diagnostic Laboratory. Alongside all our normal duties involved in operating the clinic, I was given the opportunity to work on the development of a new method for diagnosing oak wilt. Our current protocol is to break down infected branch samples sent to us and set them to incubate on petri plates in specialized media for two weeks. We check these… Read More →

New treatment for the management of Cotton Root Rot on winegrapes

Dr. David Appel, Extension Plant Pathologist with the Texas A&M AgriLife Extension Service contributed this article that describes a new treatment for one of the most devastating diseases of Texas winegrapes. This was research conducted by Dr. Appel and our own TPDDL diagnostician, Sheila McBride. -KO This disease, cotton root rot, occurs on winegrapes in the calcareous soils of Central, South, and West Texas where soil pH is well above 7. The most common symptom of CRR in grapes is a sudden wilt and death of the infected… Read More →

Leaf Gall Diagnostics

Ever wonder about how some diseases are diagnosed in a plant disease diagnostic lab.  You would be surprised that there are similarities to an ER in the hospital. When a sample arrives at the Plant Clinic, it has to be accompanied with a submission form where there are a bunch of question trying to get some history leading to the incidence or current situation.  Then the samples are triaged within 24-48 hours of receipt (dependent on diagnostician availability).  Decisions are made how to proceed based on history information… Read More →

Rose rosette

*FOR UPDATED ROSE ROSETTE INFORMATION – Please visit See how much we have gained in learning about this disease since this was posted in 2011, the pathogen that causes this disease and the vector that transmit this disease…and see how much we still do not know about this disease system* Recently there was quite a bit of “chatter” about rose rosette.  This year, we have heard of reports from parts of Texas, Ohio, Michigan, Indiana, Tennessee and some other states.  It seems that this disease is becoming… Read More →

Date Palm Decline or Cold Damage?

My colleague and collaborator, Dr. Greta Schuster at  Texas A&M – Kingsville took me around the campus to show me some of the plants where samples were taken from for our detection assay for palm phytoplasmas.  In South Texas, there has been a rash of palm trees dying.  Usually when the palms start to decline, one of the symptoms are yellowing leaves.  In fact, there are 2 related types of phytoplasmas that are well known to affect palms.  One is called Lethal Yellowing –  a common problem on coconuts in… Read More →