The Texas Plant Disease Diagnostic Lab

UPDATE (4/22/2021): We will be closed Friday, May 28th, and Monday, May 31st for Memorial day.  We will return to our normal business hours Tuesday, June 1st.

UPDATE (5/11/2021) 

NEW!  On July 1st the TPDDL will be transitioning to a new billing system which will require clients to complete a customer information form for us to be able to provide diagnostic services (Texas A&M AgriLife Extension Service requirement).  IF you will be continuing to utilize or planning to use the TPDDL for diagnostic services, please complete form AG-257 (link to form here), email the form to us – this is (should be) a one time action to register for a client #.  Thank you.

The TX Plant Disease Diagnostic Labs are operational and functioning in accordance with university rules in compliance with COVID19 action guidance. Things are still not normal and turnaround time is still impacted by staffing issues. We appreciate your patience as we will try out best to provide plant health diagnostic services.  

 Please call in advance to arrange a time to ensure that your samples are received. 

Please contact us by email IF you have received an invoice but not the report OR had not heard anything 15 business days (3 weeks) after submission of sample. We have instituted an email receipt reply notification to inform the submitter when we receive their sample and to provide a sample reference number for future inquiries related to that sample.

Homeowners are encouraged to check with their local Texas A&M AgriLife Extension Service county office for local assistance first.
The current situation is fluid and will be reassessed as new guidance and directions are given.   Please check with the lab prior to sending samples to check on operational status: updated information will be posted here and on our Facebook page ( 


Thank you for your patience and your support of the Texas Plant Disease Diagnostic Labs.

The Texas Plant Disease Diagnostic Laboratory, located in College Station, Texas, is a Texas A&M AgriLife Extension Service lab managed by the Department of Plant Pathology and Microbiology at Texas A&M University.
The Texas High Plains Plant Disease Diagnostic Laboratory  is located at the Texas A&M AgriLife Research & Extension Center in Amarillo, Texas. The THPPDDL specialized in disease diagnostics of small grains and row crops.

Our Mission:
To provide accurate and timely plant disease diagnostic support to AgriLife Extension & Research personnel, Texas Department of Agriculture, the agriculture/green industry and the people of Texas to protect and secure our plant resources and to promote economic competitiveness.

Our History:
The idea for a plant disease diagnostic service at Texas A&M University started in 1956, when Dr. Harlan Smith, the Extension plant pathologist, used it as a way to provide support to Extension personnel and growers/farmers.  In 1982, the Texas Plant Disease Diagnostic Laboratory (TPDDL) was formally established, with the appointment of Dr. Larry Barnes as its first director. In 2002, the TPDDL was called upon to be one of many universities and state labs around the country to participate in the National Plant Diagnostic Network (NPDN) and perspective region, the Southern Plant Diagnostic Network (SPDN).  This network seeks to support a (i) secure regional network for the detection and diagnosis of plant health problems, (ii) extend and support sound public policies, implement rapid and accurate diagnoses, and response strategies, and (iii) provide leadership and training. Currently, the clinic processes, on average, 2660 samples annually and supports/manages different projects under the direction of Dr. Kevin Ong and Lead Diagnostician, Sheila McBride.

Donate to help support activities at the Texas Plant Disease Diagnostic Lab. 


For assistance with plant health issues, please contact your local Texas A&M AgriLife Extension county office.  If contacting us, please email to get a quicker response. Our email contact is .  Thank you for your patience.