Erythrina Borer: All You Need to Know in a Quick Guide

Erythrina borer moths (Terastia meticulosalis) have emerged as a pest for cultivated coral trees (Erythrina spp.) in California over the past decade. These pests pose a threat to the health of Erythrina trees, which are valued for their drought resistance and beautiful flame-like flowers. Coral trees belong to the Fabaceae family and serve as a prominent feature in various landscapes across the region.

The life cycle of the Erythrina borer starts when eggs are laid on the tree, typically in the axil of leaves near stem tips. Once hatched, the larvae have cream-colored bodies and a black head, feeding on the tree and causing damage. As the infestation progresses, the health of the tree may decline, potentially leading to serious consequences if proper management is not implemented.

Erythrina Borer Basics

Identification and Life Cycle

Erythrina borer, also known as Terastia meticulosalis, is a moth belonging to the snout moths family. Here are some characteristics to help identify these moths and their larvae:

• Adult moths: Medium-sized, brownish-mottled forewings
• Larvae/caterpillars: Cream-colored bodies with a black head

The life cycle of the Erythrina borer consists of eggs, larvae, pupae, and adult moths. Eggs are typically laid singly in the axil of leaves near stem tips, and are translucent and white. The cream-colored larvae then hatch and start consuming the Erythrina plant, especially the stems. After maturing, they pupate and emerge as adult moths.

Erythrina Borer Moths

In the order Lepidoptera, Terastia meticulosalis is the most common moth species targeting Erythrina plants, while Agathodes designalis is a less common moth species doing the same. Comparing these two moths:

Both species damage the Erythrina plants mainly through their larvae’s feeding habits. It is essential to monitor Erythrina plants for signs of stem borer damage and take action if necessary to protect them.

Host Plants and Damage

Affected Erythrina Species and Symptoms

Erythrina borers mainly affect coral trees (Erythrina spp.), which belong to the Fabaceae family. These ornamental trees are known for their vibrant red flowers and seeds called coral beans. Some notable species include Erythrina herbacea, Erythrina pterocarpa, and Erythrina caffra.

The symptoms of an Erythrina borer infestation are:

• Holes in the bark
• Reddish frass in bark crevices or around the base of the tree
• Pith damage

Impact on Horticulture and Agriculture

The Erythrina borer can have a negative impact on the horticulture industry, as it can severely damage or even kill these ornamental trees. In particular, the Erythrina stem borer (Terastia meticulosalis) has been spotted in southern California and could pose a serious threat to coral trees in the area ¹.

Some key points about the Erythrina borer’s impact include:

• Damages the aesthetics of coral trees
• Reduces the lifespan of affected trees
• May lead to costly tree replacements in landscaped areas

Characteristics of the Erythrina borer:

• Larvae are creamy colored with brown heads
• Moths resemble wasps in appearance
• Can have a significant impact on coral tree health

In summary, the Erythrina borer poses a threat to coral trees in both horticulture and agriculture, damaging the tree’s bark, pith, and flowers. This can result in reduced aesthetics, shorter lifespans, and costly replacements in landscaped areas.

Geographical Distribution and Range

Expansion in North and South America

The Erythrina Borer, also known as the Erythrina Stem or Twig Borer (Terastia meticulosalis), has been expanding its range across North and South America. This pest has been sighted multiple times in southern California in 2015 from San Diego to Ventura, including areas like La Jolla, CA.

In the US, notable infestations have been reported in states such as California, Arizona, and Florida. The borer has also been spreading in the Sonoran and Chihuahuan Deserts, as well as the Baja Peninsula.

Notable Infestations

A significant infestation has been observed at the Los Angeles County Arboretum & Botanic Gardens in Arcadia, CA, where the Erythrina Stem Borer larvae have caused damage to the Erythrina plants.

In San Diego, notable infestations have occurred, affecting Erythrina caffra—a spring-flowering landscape tree—indicating a possible natural expansion of this pest in the region.

To summarize:

• The Erythrina Borer has been expanding its range in North and South America.
• Infestations have been reported in locations such as California, Arizona, Florida, and the Baja Peninsula.
• Notable infestations include the Los Angeles County Arboretum & Botanic Gardens and various locations in San Diego.

Research and Control Methods

Current Studies and Findings

A study by Andrei Sourakov at the University of California discovered the existence of Erythrina stem borer moths in California. Experts from McGuire Center for Lepidoptera and Biodiversity investigated the moth’s taxonomy and biology. They found the Erythrina stem borer belongs to Crambidae family.

Researchers used DNA analysis in their studies to better understand the moth’s genetics. Some factors that led to the spread of this emerging pest include changes in agriculture practices and increased rainfall due to Hurricane Dolores.

Prevention and Management Techniques

Currently, the main method used to control Erythrina stem borer moths is through the use of synthetic pheromones. These pheromones lure and capture adult moths. However, more research is needed to develop effective and long-term prevention and management techniques.

Pros and Cons of Synthetic Pheromones:

• Pros:
  • Target specific pests
  • Environmentally friendly
  • Non-toxic to humans and animals
• Cons:
  • Limited in scope, only effective against adult moths
  • Pheromones may not always be effective for long-term control

Scientists continue to study the Erythrina stem borer and its co-evolution with other organisms. The research conducted at the University of Texas Southwestern Medical Center and other institutions aim to develop innovative and effective pest control methods.

Life History and Taxonomy

Previous Taxonomic Changes

The Erythrina Borer, also known as the Erythrina Stem or Twig Borer, was first described by Guenée under the family Pyralidae. It has since undergone taxonomic changes by researchers like Powell and Opler, who provided better clarity on its life histories and evolutionary trajectory.

Evolutionary Trajectory

Although the exact evolutionary trajectory of the Erythrina Borer remains unclear, its life cycle displays unique characteristics, as briefly summarized below:

• Eggs: Usually laid singly in the leaf axil near stem tips, the eggs are translucent and white.

• Larvae: The larvae have a cream-colored body and a black head, developing within leaf rollers and sometimes feeding on leaf litter near the ground.

• Size: As the larvae grow, their size increases, though specific numbers and dimensions may vary.

• Season: The Erythrina Borer’s life cycle is influenced by changes of season, but exact details regarding its seasonal activity are not well established.

• Food: This species primarily feeds on Erythrina spp. (coral trees), causing potential damage to these plants.

A comparative breakdown of aspects related to the Erythrina Borer can be seen in the following table:

Some key features and characteristics of the Erythrina Borer are:

• Female borers lay eggs singly in leaf axils
• Larvae have a cream-colored body and a black head
• Feeds on and causes potential damage to coral trees (Erythrina spp.)

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Erythrina Borer

Subject: Strange looking moth.
Location: Long Beach, California
September 21, 2015 3:30 pm
I took this picture of a funny looking moth.
It’s about 1 inch long.
I have never seen anything like it before
Would be interesting to know what it is.
I took the picture late in the evening.
I live in Long Beach, CA
Signature: Stefan

Dear Stefan,
The first time we received an image of an Erythrina Borer, Terastia meticulosalis, we were stumped until a reader supplied us with an identification.  According to BugGuide, it is a:  “Tropical species that ranges north to the US from Florida to California.”

Thank you very much, Daniel!!
Stefan

Letter 2 – Erythrina Borer

Subject: Unknown moth
Location: Orange County, CA
November 26, 2015 7:17 pm
Hi. This moth was on my car window in early morning November. Irvine, So Calif. What is he??
Signature: JulieE

Dear JulieE,
Your image of an Erythrina Borer, Terastia meticulosalis, is so much better than the one we took at of offices last October.  The Erythrina Borer is an unforgetable moth.

Thank you! I could not figure it out. It was truly wonderful!!!

Letter 3 – Erythrina Borer

Subject: Moth??
Location: Southern California
November 24, 2016 2:39 pm
My father showed me a picture of this insect. We think it is a moth but have been unable to determine what insect is this. We live in Southern California and the picture was taken in September on the border of Los Angeles and San Bernardino county. We see lots of interesting and familiar insects around here but we have never seen this one before or since.
Thank you!
Signature: Tracy O

Dear Tracy,
This distinctive moth is an Erythrina Borer, Terastia meticulosalis, and according to BugGuide, it is a:  “Tropical species that ranges north to the US from Florida to California.”

Thank you so much for getting back to us so quickly. We are going to look further into this moth now that we have a name. We appreciate your help!!

Letter 4 – Erythrina Borer

Subject:  UNIDENTIFIED FLYING MOTH/INSECT?
Geographic location of the bug:  LOS ANGELES, CALIFORNIA
Date: 07/21/2018
Time: 06:53 PM EDT
Your letter to the bugman:  Can you tell me what this is, and whether I should be worried about it?  It looks like a cross between a moth and a scorpion (turned up and pointed lower body).  It has been sitting on my window (outside) all day.
How you want your letter signed:  Sheila Wasserman

7:12 PM
I am thinking that this poor moth has deformed wings and that it cannot fly.  It has been in the same position all day on my window.  Is there anything I can feed it –I can try to get it into a flower bed and leave some water in a tiny cap.  But otherwise, I don’t know what to do with it.

Dear Sheila,
Your moth is an Erythrina Borer, Terastia meticulosalis, and it is not deformed.  Moths are often attracted to porch lights and we suspect it will eventually fly away.  According to Featured Creatures:  “The marbled-brown forewings of Terastia meticulosalis make this species cryptic when at rest. However, its hind wings are white”  and “The young larvae of Terastia meticulosalis are found inside the stems of Erythrina herbacea, where their feeding produces a characteristic dying-off of the tip of the host plant.”  The host plant is commonly called a coral tree and according to Los Angeles Almanac it is the official tree of the City of Los Angeles.

Letter 5 – Erythrina Borer visits WTB? offices

Erythrina Borer attracted to porch light
Location:  Mount Washington, Los Angeles, California
October 25, 2015
Upon walking out the front door this morning, we noticed this little Pyralid Moth that we recognized because of previous submissions.  There must be a coral tree nearby to have provided food for the caterpillars.

Letter 6 – Unknown Moth is Erythrina Borer

strange moth
Location: near Macon, GA
August 4, 2011 3:39 pm
I saw this moth outside my house yesterday (Aug 4 2011). I’ve never seen one before (having lived in the area for nearly a decade) and was hoping you could help me identify it. The back part of it is especially odd to me; it reminds me of a spinal column almost. The pictures are cropped to limit size, but hopefully they offer enough detail for you to be able to tell.
Signature: J

Dear J,
We tried and we failed.  Perhaps one of our readers will have better luck trying to identify this unusual moth.

Thanks to a comment, we now know that this is a Erythrina Borer, Terastia meticulosalis, and we verified that on BugGuide, but other than a food plant for the larva and a range that includes some southern states, we did not learn much else.  Erythrina is the genus name for a group of trees we have always called Coral Trees, and since some species are native to the warmer states, the moth might also be native.  We also located a link to a technical paper written in 1922 by O. H. Swezey, entitled The Erythrina Twig-Borer (Terastia meticulosalis) in Hawaii (Pyralidae, Lepidoptera).  Here is a citation from that paper:  “Dyar, in Journal of the New York Ent. Soc, IX, 21, 1901, describes the larva from Erythrina herbacea in southern Florida, and says: ‘The larva is an internal feeder, boring in the younger stems which it completely hollows out, killing them. When the plant is in early flower, the young flower heads are often killed and webbed up into a foul mass by this larva. Spins a large webby cocoon in the ground.'”

Reader Emails

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Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Erythrina Borer

Subject:  Moth
Geographic location of the bug:  San Diego CA
Date: 11/14/2017
Time: 07:34 PM EDT
I found this moth today at work. 11-14-17. I was wondering what it was.
How you want your letter signed:  Doug

Dear Doug,
This very distinctive moth is known as an Erythrina Borer, Terastia meticulosalis.  According to BugGuide:  “The only species in the genus found in America north of Mexico.”