Category Archives: Seen at TPDDL

Rapid Decline of Oaks

Ms. Sheila McBride (TPDDL diagnostician) and Dr. David Appel, Extension Plant Pathologist with the Texas A&M AgriLife Extension Service contributed this article to address the numerous inquires that has been received this year regarding declining oak trees -KO This year, beginning in the early spring to late summer, there has been many inquiries as to why the post oaks have “suddenly” died. The most frequent symptoms have been described as a rapid appearance of chlorotic (yellow) and/or necrotic (brown and dead) leaves throughout the entire crown. The leaves often… Read More →

Are Lichens Killing Your Trees?

         One of the most common mutualistic relationships in the plant world is that of lichens. Made up of one part filamentous fungi and one part algae or blue-green bacteria, lichens are not considered a “true species.” The unique combination results in a very hardy, weather-tolerant, and genetically diverse group of Nitrogen fixers that is practically self-sufficient. The fungal partner cannot survive alone, but instead thrives on the availability of photosynthetic products provided by the algae or bacteria. Lichens are common pioneers on trees, shrubs, soil, and even… Read More →

Cladoptosis: An interesting phenomenon

Cladoptosis is a process in which trees shed their branches or “self-prune” as part of their normal physiology or in response to stress through the formation of an abcission layer at the branch base. Sources of stress which may contribute to this shedding include drought, soil and root compaction, or presence of disease. In the case of certain tree species, however, none of these factors need be present in order for Cladoptosis to occur. For some tree species, including larches, pines, poplars, willows, maples, walnut, ashes, bald cypress, and oaks,… Read More →

Identifying bacterial infections in submitted plant samples.

This is another assignment submitted by BESC484 student, B. Commer, as a partial requirement for the course.  We typically get an uptick of bacterial issue showing up in the TX Plant Clinic in the fall. One of the student’s assignment is to document what they do in a manner to explain to non-plant pathologist or microbiologist what they do.  Enjoy- KO   Ever wonder just how the diagnostician can confirm bacterial plant pathogens? It starts with a very simple yet fascinating test to check for what is called… Read More →

Broadmite damage on tomatoes

One the assignments that are given to undergraduate BESC 484 students who interned at the Texas Plant Disease Diagnostic Lab is to write blog post articles of things that might interest them.  This fall, Blake Commer will be providing several of this write-up to fulfill partial requirement for this writing intensive course.  Recently, the Plant Clinic received a tomato submission with broad mite damage. The following is a write up about the broad mite on tomato. Enjoy. -KO Broad Mites Causing Leaf Curling and Stunting in Tomato Plants… Read More →