Pecan Tree Visitors

Panhandle residents have seen caterpillars in abundance this June. One common visitor to pecan trees is the Walnut Caterpillar Datana integerrima. The walnut caterpillar has a very narrow host range and feeds only on trees in the Juglandaceae family which includes walnut, pecan, and hickory trees. They are sometimes seen on other plant material, but feeding on non-host plants is unlikely.

Walnut caterpillar feed on the leaves of host trees through several growth stages and molts until they have reached the final larval instar and are ready to pupate into an adult moth. Their color changes from light green when newly hatched to reddish-brown to almost black with long white hairs as they mature. The caterpillars group together in large masses and may hang from each other and dangle from the tree branches when molting. Instead of creating a cocoon in the tree, the walnut caterpillar moves to the ground beneath the tree and burrows into the soil or leaf litter to pupate and emerges later as a moth.

What can you do if your pecan tree is hosting walnut caterpillars?

Although the numbers seen on trees may be alarming, a healthy tree can tolerate some feeding damage. Stripped branches may increases the chance of a lower yield of fruit because the removal of leaves does reduce the amount of energy the tree can produce, but overall health of the tree should not be significantly affected. However, many homeowners find falling caterpillars and their excrement unappealing and may decide to take steps to manage the population.

There are several natural enemies that feed on caterpillars, so avoid using a broad spectrum insecticide that might harm predatory insects and other animals. Consider using a biological control product such as Bt (Bacillus thuringiensis) that is only lethal to caterpillars. Other methods are “pick and squish” or drowning in a bucket of soapy water. Next year, in the spring, watch for masses of tiny green eggs on the underside of leaves and remove and destroy them before hatching.

For more information visit USDA Forest Service Forest Insect & Disease Leaflet 41 “Walnut Caterpillar”


Posted: July 1, 2014

Category: Horticulture
Tags: Caterpillar, Fruit Trees, General Gardening, Insects, Panhandle Gardening, Pecan, Pests


Robert Rhodes
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I was interested in deploying a memorial artificial reef in my father's name. Something like pyramid structures. I was wanting information on how to go about this and are there companies that have and deploy these structures.

Scott Jackson

May 28, 2021

You will need the minus sign. In the ArcGIS search box type in the Decimal Degree conversion. for Fountain Bleu Box Cars -85.8833, 30.15

May 2, 2021

How do you put the negative number when I try to enter without no (-) tells me I am 4,000 miles away

April 26, 2019

Just a quick note thanking you all for providing valuable recovery information and tools.


February 13, 2019

Hi Susan, Registration opened on the 11th, and future events will also be 10 days before the event. The link to register is here If you have any trouble getting signed up please email me at I apologize for the delayed response, notifications on the website are not sent directly to me. Julie

Susan Higby
January 20, 2019

Hi Julie, When do you expect to open up ticket purchases for the next seminar on February 21st? Thank you so much for these series! Susan Higby

Scott Jackson

July 3, 2016

Latest release from Health Department in Bay County / Bay County TDC via Twitter June 28, 2016

Detlef VanderMeer
June 17, 2016

Yes, I had a call about this problem this morning, they are here in Bay County

May 6, 2016

I noticed aphids on my lettuce and planned to take them in to show some students. On the planned date I found they they had been consumed by parasitic wasps. I felt it was a sign of a balanced ecosystem.

February 3, 2016

Where can I find seed potatoes (red)? I am in Gulf Breeze.

Ava Laurie
July 22, 2015

I was actually wondering about the issue with the mower blades. I am constantly getting the ends of the grass cut on a way that has the tip of it drying out. Is the fact that the blades are a little worn, that is causing this issue of the grass getting dry at the top.

Kristal Walsh
June 8, 2015

For sure on the Aucuba! I love it and use it throughout my front yard along with the cast iron plants. One of my favorite shade plants however is the Apostle's Iris, 'Neomarica gracilis'. They have survived the coldest winters so far and have come back beautifully. Thanks for the article. I have 2 shady beds I am renovating right now so I look forward to finding the Japanese Plum Yew and the Mahonia!

Ann Jeffcoat
April 19, 2015

An evergreen shrub that does well in the shade for me is Aucuba japonica 'Serratifolia' An all green aucuba.

Earl Mirus
April 15, 2015

Nice article Julie. Just a side note that occurred to me as I looked at the pictures. Please don't recommend (I know you didn't in this article) that people plant close to the flare roots of a tree. The first radial distance of 3x the DBH of the tree is very, very important root area and what the arborist needs access to for many treatments. As important, perhaps more important is: 1. the tree trunk and exposed flare roots need to be dry when it is not raining and having vegetation in close proximity eliminates the breeze and keeps the tree trunk damp creating a decay/fungi opportunity; 2. cast iron plant, Jasmine, fern, etc. are major competitors in that critical root area. If a tree is stressed one of the cultural remedies is to clear out plants in that critical root area and install organic mulch, preferably pine straw. Keep up the good work!!

Julie McConnell
March 26, 2015

Hi Stan, I don't know how frequently that is done, however, if the gardener plans to change out the plants after a very short period of time they may leave them in containers. Some commercial properties may do that if they plan to swap out if anything declines (theme parks, other high profile spots), but most plants should not stay in original containers indefinitely. Eventually the plant's root system will outgrow the pot and will be unable to take up enough water to sustain itself. Julie

stan luczak
March 14, 2015

Miss McConnell, Is it a common practice by some homeowners to leave the annuals in their pots when they plant them in the Spring? Thank you

Julie McConnell

December 5, 2014

Hi David, The palm you are describing is likely Butia capitata also known as Jelly Palm or Pindo Palm. The fronds have a bit of a blueish or silvery color to them that makes them fairly distinctive. More can be found about this palm at the following link If you like, send a picture to my email and I can confirm if that's what you have. Have a great day! Julie

David Schoepf
December 4, 2014

We have a palm, locally known as a Jelly Palm" It's a very slow growing, like 12 feet in 15 years, and very bushy compared to the typical King palm. It puts out small groups of flowers, inside a hard, 3-4 ft. long woodlike, split, shell, which, of course become seeds. That is apparently what some old timers used for "Jelly:". Jelly Palm is not likely it's correct name. From that vague description, can you tell me what it is, or if not, what I can provide to help properly name it.

Lesia Andrews
November 5, 2014

Please give me a call. I would like to discuss how Farm Credit can be involved in this program. My number is 850-718-5511. Thanks, Lesia Andrews

Julie McConnell

September 7, 2014

Hi John, Butterflies are rather specific about where they lay eggs and which plants their larvae (caterpillars) will feed on. For the Gulf Fritillary, the passionflower vine is the preferred larval host. I would not expect having this plant in your garden would have any direct effect on the number of caterpillars that would target tomatoes and peppers. If you would like to learn more about pests that are more specific to tomatoes and peppers, please see the following publication at "Insect Management for Tomatoes, Peppers, and Eggplant"

John Nelson
September 3, 2014

if I plant this purple passionflower....will caterpillars start eating my tomatoes and green bell peppers. Thanks John Nelson

Julie McConnell

July 3, 2014

Glad to hear it, have a wonderful weekend!

July 3, 2014

Worked like a charm!

Julie McConnell

July 3, 2014

Hi Suzy, The link should take you to a leaflet publication by USDA Forest Service titled "Walnut Caterpillar." I checked the link embedded in the article and it is working tonight, but sometimes there can be other issues. I am adding the link below in plain text so that you can try to copy and paste into your internet browser. If you are still unable to access it I would be happy to scan it and send it to you directly as a .pdf in an email next week. Julie

July 2, 2014

Your link to the US Forest Service is not valid

Donna Legare
February 19, 2014

It would be great if you would submit this article for newspaper publication, especially Tallahassee Democrat. There are so many people that are misinformed about lichens and Spanish moss. Donna Legare Native Nurseries

Jonnie Smallman
December 3, 2013

Enjoyed your article. Wish I had time to plant winter annuals.

November 25, 2013

Noticed one of our longleaf pine saplings, in the middle stage has died out on the top 3" of the bud. The trunk and several lower limbs still have healhty green looking growth buds. We are located 3 blocks north of the Gulf of Mexico in Franklin County Fla. elevation +27' sandy soil. Approximately 25 trees are @200yr old, some cat faced. Another 50 trees are post turpentine era, and another 75 are in the grass and middle stages. We eliminated all the loblolly pine 10yrs ago in hopes of restoring the longleaf presence on our 4+acres. Regards, Paul Standish

Julie McConnell

November 19, 2013

Thank you, Phil!

Phil Smith
November 19, 2013

Excellent article! One of your M.G.'s ...Phil_Smith...

Matthew Orwat
September 10, 2013

What type of grass do you have? If you have centipede, you will not need any additional fertilizer for the season. How much did you put out in August/

Kenneth Smith
September 10, 2013

Applied fertilizer to grass early August as I was away for 5-6 months. Can I apply again on 9/15?

Scott Jackson

January 10, 2013

To register and view the draft agenda please visit:

Scott Jackson

January 10, 2013

To register and view the draft agenda please visit:

Scott Jackson

November 14, 2012

Have any favorite seafood recipes for the Holidays or maybe a treasured family memory? Post a comment and share!

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