Texas Plant Disease Diagnostic Lab-
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Category Archives: trees
Actinopelte Leaf spot
The following is a blog post writing assignment from 2013 summer BURS (Bioenvironmental Undergraduate Research Scholar) and BESC 484 student, A. Brake. As previously mentioned, the student is asked to submit a short write up of something that interest them (related to plant pathology) which they may have seen or heard about in the Plant Clinic. They are also highly encouraged to take photographs of subject (training in photo documentation). Ms. Brake submitted a couple of excellent photo with her assignment below where she used a Dino-lite digital… Read More →
In our email box – live oak leaf drop….NOT
About a week ago, I got an email in our PlantClinic box about live oak. The gentleman had read my blog post on the annual texas live oak leaf drop (March 2011). He had a very interesting question based on his observation of this tree. Below is the email he sent: After many years of watching my live oak trees lose their leaves every April – this year, one of them did not lose its leaves. Is this something to be concerned about? Was it last years drought… Read More →
In our email box – galls on live oak
Recently, I received an email via our PlantClinic email with a couple of photo wondering if the pea-sized “balls” on their Texas live oaks might be “fatal” to the trees. This is one of the few times that I get to give a happy reply. Those galls on the oak leaves are caused by insects… gall-making insects. This is quite typical on oaks in Texas. Rarely, do these galls ever kill an established tree. I say rarely, because I remember a situation about 8 years ago when we… Read More →
Algal leaf spots on Magnolia (Training at the Plant Clinic part 4)
Blog article #4 by Marissa McCarthy (for partial fulfillment of BESC 484 requirement) Algal leaf spot is caused by the subcuticular leaf parasite from the genus Cephaleuros. This specific algal leaf spot is C. virescens and was sent into the lab on a magnolia from a private residence. Cephaleuros thrives in environments that are warm with high humidity, or poorly aerated soils. Characteristically this algae is harmless, causing only minor leaf spots on the upper surface of leafs that are raised, textured, orange to brown in color, with… Read More →
Tar spots on oaks (Training at the Plant Clinic part3)
Blog article #3 by Marissa McCarthy (for partial fulfillment of BESC 484 requirement) Trabutia quercina is an ascomycete fungus that specifically targets species of oak trees, creating a disease commonly known as Tar spot on the leaves. The Tar spot was found on a live oak sample that was sent into the lab from a private residence. This fungus is characterized by the formation of black, blotchy lesions on the upper side of oak leaves, especially along the veins of the leaves. The lesions gradually expand and… Read More →
