Roots, Shoots, Fruits & Flowers: Walnut Caterpillars, Honeybee Infestations, Rabbit Damage, Early Ragweed, and Boron Deficiency

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Walnut caterpillars on a pecan tree. Photo: Brenda Laurence, Master Gardener, Merryville, LA

Walnut Caterpillars

Brenda, a Master Gardener, sent an image and wanted to know, “I guess this is walnut caterpillar on my pecan tree?”

Yes, Brenda is correct. Her picture is interesting because she has both the fourth and fifth growth stages of the walnut caterpillar feeding at the same time at the same place. Because Brenda has a small tree, AHA suggested Sevin® or Malathion®, then Brenda asked about Bt or Bacillus thuriengensis. Products like Dipel® and Thuricide® have Bt, a pathogen of caterpillars, as its active ingredient.

Honeybees under a porch.

Bee under porch decking. Photo: Brueggen's Bees. Shepherd, TX.

Honeybee Infestations

A homeowner asked AHA for assistance to remove honeybees from under his porch. AHA contacted beekeepers to help this homeowner.However, no beekeeper was interested because the homeowner self-treated his nuisance bees with an insecticide, and the colony was contaminated with pesticide. The take-home message is to avoid killing honeybees in structures. If bees are successfully killed, several negative results will occur:

  • Honey leakage and structural staining,
  • Honey fermentation and odors, and
  • Cockroaches and ants’ infestation due to the fermented honey.

Damage done by rabbits.

Bean plant with wildlife damage. Photo: Angela Schoenfeld, Master Gardener, Rosepine, LA.

Rabbit Damage

Angela asked about a new pest problem, “Now I have a new problem. My green beans were coming up fine but now I see something is eating the leaves. Probably a rabbit….”

Repellents are a solution for preventing animal damage. The University of Florida Extension listed several products labeled to repel rabbits in vegetable gardens:

  • Deer Off™
  • Rabbit & Groundhog Out™
  • Deer Pharm™
  • Hinder™
  • Miller Hot Sauce™
  • Hare-less Animal Repellent™.

The way these repellents work is to deter rabbits by odor and by taste. Some products use capsaicin, the active ingredient in hot peppers. Other products use egg protein or garlic to repel rabbits. All the products listed above are applied by spraying. As always, read the label for safe and effective application.


Ragweed infesting a lawn. Photo: Eric Reed, Lake Charles, LA.

Early Ragweed

Eric is struggling with his lawn, “I have ragweed taking over a part of my St. Augustine lawn. The area is struggling to come back to life this year. What do you recommend I treat the lawn with to get rid of it.”

AHA replied, “You can use Weed-B-Gon® to control weeds on lawns. This product is selective against broadleaf weeds and safe for turf. Also, Image® with atrazine will also select against broadleaf weeds and be safe for your St. Augustine.

Weeds thrive on site with low fertility. Let me encourage you to have your soil tested and then lime and fertilize according to the recommendation with your test results. You can obtain a soil sample kit at your nearest AgCenter office.

Another practice to help your St. Augustine is to raise the mower height to three inches.”

Zoysia with possible deficiency.

Zoysia grass with possible boron deficiency. Photo: Nehemiah Loftin.

Boron Deficiency

Nehemiah also asked about his lawn, “I have Zenith Zoysia that I planted last year. My grass in places has this golden color. I thought it was a fungus, so I put down Scott’s Disease X and Propiconazole about a month ago. It is still there. Also done a soil test. I am not sure what is going on and seeing if you had any insight.” Nehemiah also shared the results of a soil test, and in general, the nutrients level looked good except for boron.

Boron can be applied according to the rates listed recommended by the manufacturer’s label. Dr. Ron Strahan, the lawn specialist with the AgCenter, also added, “Along with applying boron, I would aerate this lawn. Compacted soils will cause stress like this as well.”

If you want to contact Roots, Shoots, Fruits, and Flowers, please send your questions and pictures to Keith Hawkins, Area Horticulture Agent (AHA), 337.284.5188 or

“Before you buy or use an insecticide product, first read the label, and strictly follow label recommendations. Mention of trade names or commercial products in this article is for informational purposes only and does not constitute endorsement by Louisiana State University AgCenter.”

“This work has been supported, in part, by the USDA National Institute of Food and Agriculture, Renewable Resources Extension Act Award, Accession Number 1011417.”

7/17/2023 7:15:49 PM
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