Two egg sacs by a spider.
Chaery of DeRidder asked very simply, “What causes this?”
At first, AHA thought the white areas on the leaf were caused by powdery mildew, a fungal disease. However, after enlarging the image, he notice that image looked like “grains”. An insect specialist from the AgCenter thought these white areas are egg sacs from a spider. Except for the venomous spiders, spiders are predators and will eat insects. Neem oil would smother the eggs and prevent a hatching. However, these oils can burn plants at high temperatures so read the label to learn the safe temperatures.
A crape myrtle improperly pruned.
This is an image of a crape myrtle with improper pruning. This practice will ultimately shorten the life of a crape myrtle tree. There is a belief this practice will make more blooms. However, the tree will make the same number of blooms, but they are concentrated. The sprouts are weakly attached and may cause further damage if the sprout breaks off. The best way to help trees affected by “crape murder” is to simply stop.
A tomato plant with herbicide damage.
Ms. Charlotte brought a sample from a tomato plant with an unusual symptom similar to the one in this picture.
The tomato in this image has the classic symptoms of herbicide damage from glyphosate, the active ingredient in products like Roundup ®, RM43®, Zap-It ® and many other herbicides. Tomatoes are very susceptible to drifting glyphosate so gardeners need to be aware of wind speed and direction when using glyphosate products in the area of tomatoes and other vegetables.
A pecan with galls caused by phylloxera, an insect pest.
One homeowner brought in a sample from his pecan tree, and this sample had galls similar to those in this image.
The galls in this image are from an insect called a phylloxera and are brood chambers for this insect pest. The good news is that this pest is mostly a cosmetic nuisance and will not substantially harm a pecan tree.
However, if a homeowners wants to treat for phylloxera next year, then an insecticidal soil drench before pecan trees leaf out may be a solution. A product like Martin’s Dominion Tree & Shrub Insecticide ® can be applied as a soil drench. As always, read the label before application.
If you want to contact Roots, Shoots, Fruits and Flowers, please send your questions and pictures to Keith Hawkins, Area Horticulture Agent (AHA), 337-463-7006 or firstname.lastname@example.org. Also, please share the name of your parish.
“This work has been supported, in part, by the USDA National Institute of Food and Agriculture, Renewable Resources Extension Act Award, Accession Number 1011417
The LSU AgCenter and the LSU College of Agriculture