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Is this Bacterial Leaf Scorch on a Live Oak? #794842
Asked June 08, 2022, 8:16 AM EDT
This Live Oak was planted in College Station, Texas on May 25, 2022. The majority of the dead leaves are on the inside of the canopy, and many have very dark veins. I originally thought it was water causing the dead leaves, but the soil moisture was good. I did notice many insects around/on the tree that appeared to be a piercing/sucking insect (see pictures "Insects on Stems" and "Holes in Leaves"). I then took a couple of individual leaves from the tree. I noticed necrotic tips and necrotic areas between the veins, but also a yellow hue around all necrotic spots towards the inside of the leaf (see picture "Leaves Close Up_Off Tree") on one of the leaves. The other individual leaves were brown but had a darker veinal area than the rest of the leaf. I'm wondering if this is the beginning stages of Bacterial Leaf Scorch (Xylella fastidiosa)? If so, can the tree be treated?
Brazos County Texas
Expert Response
Mallory,
Great, clear photos! Those insects are glassy winged sharpshooters but don't pose a threat to the oak. They are everywhere this year and are the cause of all the water misting down from beneath trees, including crape myrtles.
I don't see signs of Xylella and don't consider it to be a big treat to live oaks in general. The brown areas have signs of young caterpillar or sawfly damage/feeding. This appears as tissues eaten away leaving the network of veins behind. At the very young age they haven't molted and grown a larger set of mouthparts so as to be able to eat more of the leaves. These caterpillars are usually kept in check by natural enemies and the damage although unsightly is minor and doesn't require spraying. In fact spraying can kill the natural enemies that are helping avoid more significant damage.
Let me know if you have any additional questions.
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May I keep and use your photos?
