Genista Caterpillar: All You Need to Know for Effective Control and Prevention

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The Genista Caterpillar, also known as Uresiphita reversalis, is the larval stage of a moth species that commonly affects plants like Texas Mountain Laurel and Baptisia. These caterpillars are not only fascinating creatures but are also essential to consider when maintaining the health and beauty of your garden or landscape.

These inch-long caterpillars come in shades of green to orange and can be identified by their black and white hairs. They differ from fall webworms as they have fewer hairs and no distinctive double row of black dots on their body segments. Regularly seen in Central Texas and Gulf Coast landscapes, these caterpillars create webbing on foliage and feed on host plants, which can lead to damage if not addressed.

Some key features of the Genista Caterpillar include:

  • Green to orange body color
  • Black and white hairs
  • Feeding on Texas Mountain Laurel and Baptisia plants

Understanding the life cycle and behavior of the Genista Caterpillar is vital for proper pest management. By learning about these insects, you can better protect your plants and ensure a flourishing garden or landscape.

Genista Caterpillar Identification

Physical Appearance

The Genista Caterpillar, also known as sophora worm, has a distinct appearance. Their body color ranges from green to orange and they have black and white hairs. Unlike fall webworms, they lack a double row of black dots on the top of each body segment.

Life Cycle

  • Eggs are laid in clusters by the adult moth, usually on the undersides of leaves
  • The larva (caterpillar) stage is when they feed on foliage
  • Pupation occurs after the larval stage
  • The adult moth emerges from the pupa, completing the life cycle

These caterpillars can be found in various regions, including California and Canada.

Adult Moths

The adult form of the Genista Caterpillar is the Genista Broom Moth (Uresiphita reversalis). The moths are light to medium brown, with a dark spot on each top wing. Their hindwings are yellow or orange with some brownish-gray shading toward the edges.

Comparison Table between Genista Caterpillar and Fall Webworm:

Feature Genista Caterpillar Fall Webworm
Body Color Green to orange Pale green
Hairs Black and white Longer and more
Black Dots None Two rows

Host Plants and Distribution

Texas Mountain Laurel

The Genista caterpillar is commonly found on the Texas Mountain Laurel (Sophora secundiflora) 1 . This small native tree is often used in landscaping and provides a suitable environment for the caterpillar to thrive. Some key features of the Texas Mountain Laurel are:

  • Belongs to the pea family
  • Produces beautiful purple flowers
  • Native to the Southwestern US and Northern Mexico

Honeysuckle and Broom Plant

In addition to the Texas Mountain Laurel, Genista caterpillars are also attracted to Honeysuckle and Broom Plants 2. These plants share similar characteristics:

  • Part of the pea family
  • Provide nourishment and shelter for the larvae
  • Grown throughout the South and Mexico

Range and Habitat

Genista caterpillars are commonly found in central Texas landscapes and throughout the Gulf coast 3. The range and habitat of these caterpillars include:

  • Southwestern United States
  • Northern parts of Mexico
  • Areas with an abundance of host plants like Texas Mountain Laurel, Honeysuckle, and Broom plants
Feature Texas Mountain Laurel Honeysuckle Broom Plant
Plant Family Pea Family Pea Family Pea Family
Common Location Southwestern US South & Mexico South & Mexico
Caterpillar Genista Caterpillar Genista Caterpillar Genista Caterpillar

Impact on Plants and Environment

Defoliation

Genista caterpillars are known to cause defoliation of plants, primarily affecting Texas mountain laurel. These caterpillars form loose webbing on the foliage and feed on it, leading to defoliation in plants1. This can occur during:

  • Fall: Defoliation in this season may decrease the overall health of the plant.
  • Spring: Defoliation during this time might affect new growth and bud formation.

New Foliage Damage

Due to their feeding habits, Genista caterpillars can cause significant damage to new foliage. The caterpillars prefer tender, new growth, which makes plants susceptible to:

  • Stunted growth: Damaged new growth and buds can result in slow or stunted growth of the plant.
  • Aesthetic damage: The visible damage to foliage can impact the appearance of the plant.

Alkaloids in Caterpillars

Genista caterpillars are known to contain alkaloids2. The ingestion of these alkaloids by predators can lead to potential risks such as:

  • Toxicity: Consumption of caterpillars with high alkaloid content can lead to toxic reactions in the predators.
  • Defense mechanism: This natural protection allows Genista caterpillars to deter or defend against potential predators.

Comparison of Defoliation and Alkaloids in Caterpillars

Aspect Defoliation Alkaloids in Caterpillars
Main impact Plant health and growth Predators and caterpillar defense
Affected areas Foliage, buds, and new growth Predators consuming caterpillars
Potential risks Stunted growth, reduced plant health, aesthetic damage Toxicity, defense mechanism

Control and Management

Biological Control

A popular and eco-friendly method to control genista caterpillar is using Bacillus thuringiensis (Bt), a natural soil-dwelling bacterium. Bt specifically targets caterpillars and harmful insects, leaving the beneficial ones unharmed. For example:

  • Pros: Environmentally friendly, doesn’t harm beneficial insects
  • Cons: Needs to be applied when larvae are young, may require multiple applications

Chemical Control

Chemical insecticides can be effective against genista caterpillar, but should be used cautiously due to potential harm to beneficial insects and the environment. Some active ingredients used in chemical control are:

  • Spinosad: Derived from a naturally occurring bacterium, safe for most beneficial insects, and effective against younger larvae1.
  • Pyrethroids: Synthetic chemicals with a low environmental impact, they target a wide range of pests, including genista caterpillar2.
Insecticide Pros Cons
Spinosad Natural, safer for beneficials Less effective on older larvae
Pyrethroids Low environmental impact, potent Non-selective, may harm some beneficials

Physical and Mechanical Control

Physical and mechanical control methods can be used to manage genista caterpillar infestations. Examples include:

  • High-pressure water sprays: Dislodging larvae and pupae from their host plants with a strong blast of water from a garden hose3.
  • Pruning: Removing infested branches and foliage to reduce caterpillars’ habitat and food sources4.

High-pressure Water Sprays

High-pressure water spray can be used to dislodge larvae and pupae from host plants. This technique should be applied early in the morning or late in the afternoon.

  • Pros: No chemicals, affordable, easy to use
  • Cons: Inefficient for large infestations, may need multiple applications

Pruning

Pruning infested branches and foliage can help reduce caterpillar populations and prevent the spread of pests. This method is particularly helpful for protecting Texas mountain laurels5.

  • Pros: No chemicals, improves plant health
  • Cons: Time-consuming, may not completely eradicate infestation

Natural Predators and Enemies

Birds and Lizards

Genista caterpillars have some predators in the wild, two of which are birds and lizards. For example, birds like the mockingbird consume the caterpillars for nutrition, while lizards such as anoles and geckoes might prey on them as well.

Parasitic Wasps

Another group of natural enemies for the genista caterpillar are parasitic wasps. These insects can be beneficial in controlling genista caterpillar populations. Specifically, parasitic wasps like ichneumonids and braconids target genista caterpillars as hosts for their offspring.

Other Insects

In addition to birds, lizards, and parasitic wasps, other insects also act as natural predators for genista caterpillars. For instance, some insect predators include ground beetles, true bugs, syrphid fly larvae, and lacewing larvae that help in controlling caterpillar infestations source.

Comparison of Natural Enemies

Natural Enemy Characteristics
Birds * Consume for nutrition
Lizards * Prey on caterpillars
Parasitic Wasps * Control caterpillar populations
Other Insects * Provide additional predator control

Related Caterpillar Species

Fall Webworms

Fall Webworms are a type of caterpillar that infests a variety of tree species. They spin a silk web around leaves and branches, providing them shelter while feeding. Some key features of Fall Webworms include:

  • Light-colored larvae with dark spots and long hairs
  • Create large, unsightly webs on trees
  • Feed on leaves within the web

Similar to the sophora worm (genista caterpillar) that is found on Texas mountain laurels, Fall Webworms also create webbing around foliage. However, their diet and preferred host plants differ significantly from genista caterpillars.

Tenting Caterpillar

The Tenting Caterpillar, also known as the Forest Tent Caterpillar, is another species that builds silk structures in trees. Differentiating features of Tenting Caterpillars are:

  • Blue and orange-colored larvae with white spots
  • Create silk tents on tree branches
  • Move in a line, following silk trails laid by leaders

Compared to the genista caterpillar, the Tenting Caterpillar’s silk structure is more like a tent than a web. They also exhibit a different feeding and movement pattern.

Genista Caterpillar Fall Webworms Tenting Caterpillar
Silk Structure Webbing around foliage Large webs on trees Silk tents on branches
Feeding Texas mountain laurels Various tree species Leaves of various trees
Larvae Appearance Black or brown with spots Light-colored, long hairs Blue and orange, white spots

As seen in the comparison table, Genista Caterpillars, Fall Webworms, and Tenting Caterpillars all produce silk structures but differ in their feeding habits and larvae appearances.

Generations and Survival Tactics

Multiple Generations per Year

Genista caterpillars typically have two generations a year in the southern regions. The egg-laying process involves multiple batches of eggs laid on the undersides of leaves, with each batch containing up to 70 eggs, allowing for a substantial population growth.

Overwintering and Pupation

When it’s time to pupate, genista caterpillars create thin white cocoons attached to various surfaces, such as vegetation and buildings. Overwintering helps them survive colder months and resume their life cycle in the spring. Some effective measures for managing genista caterpillar populations include:

  • Regularly inspecting brooms and other host plants
  • Removing infested leaves and cocoons
  • Applying insecticidal soaps if the population is high

Pros of insecticidal soaps:

  • Safe for most beneficial insects
  • Biodegradable
  • Low toxicity for humans and pets

Cons of insecticidal soaps:

  • Can harm some sensitive plants
  • Must come in direct contact with caterpillars
  • Multiple applications needed for effectiveness

Comparison: Generation 1 vs Generation 2

Feature Generation 1 Generation 2
Timing Spring Late Summer
Host Plants Brooms, Texas mountain laurel Brooms, Texas mountain laurel
Pupation Thin white cocoons Thin white cocoons

In conclusion, understanding the life cycle and survival tactics of the genista caterpillar is essential for effective population management. Regular inspection and timely insecticidal soap applications can help control these caterpillars and protect brooms, Texas mountain laurels, and other host plants.

Footnotes

  1. Genista Caterpillar on Texas Mountain Laurel 2 3

  2. Host Plants for Butterflies 2 3

  3. Genista Broom Moth / Genista Caterpillar 2

  4. http://hortipm.tamu.edu/pestprofiles/pruning-genista-caterpillar

  5. [https://landscapeipm.tamu.edu/genista-caterpillar-on-texas-mountain-laurel/]

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 – Genista Caterpillar from Florida

 

Genista Caterpillar
Hi,
I found your website checking on the Genista caterpillar. I’ve attached two pictures of them on the Lupinus diffusus in Polk County, Florida. I had sent the pictures to an Entomology Dept. at University of Florida for an ID. I read with interest your posting of the caterpillar on another plant.
Paul Eisenbrown

Hi Paul,
Thanks for sending the photos. Genista Caterpillars are not very common online.

Letter 2 – Genista Caterpillar

 

hairy green caterpillars on sophora tomentosa
Hi,
These hairy green caterpillars were on a necklace-pod plant (sophora tomentosa) in Vero Beach, FL which is mid-way up the Atlantic coast of Florida (at the northern limit of the tropical zone). The cats are about 1 1/2 inches long. Since the photo was taken one of them has pupated in a cocoon on the underside of a necklace-pod leaf. Your ID help is really appreciated. I can’t find any references which show necklace-pod as a host plant for any butterflies or moths and haven’t been able to find a match to the caterpillar on the internet.
Keep up the good work and thanks for your help!
Kathleen Scott

Ed. Note: Before we could identify Kathleen’s caterpillars, she wrote back with the following information.

Daniel,
Thank you so much! Unfortunately I didn’t collect the pupa. It is no longer on the plant and I didn’t find any others (of course the cats might have crawled off to pupate in other places). I continued to search the internet and finally got an identification. I’m sorry to be late in telling you. When I went back to your site to let you know there was an odd error message about the site being offline because it had exceeded its allowed number of hits. It slipped my mind to try again later, I apologise. You offer a great assistance to the public and are a wonderful resource.
The caterpillar is a Genista Caterpillar, Uresiphita (=Tholeria) reversalis (Guenee) (Lepidoptera: Pyralidae). The references I found for it were about Arizona, Texas and the Pacific Northwest. In Texas it feeds on mountain laurel, crape myrtle, honeysuckle & laburnum. Other references said that it’s one of the few predators of Scotch Broom, an invasive exotic (legume family) in the Pacific Northwest. Apparently the caterpillar absorbs alkaloids from its host plants & is then unpalatable to predators. The following site states that the caterpillar is in the web-worm family and destructive to trees in Texas. I was very puzzled that I couldn’t find any data relating to the caterpillar as a pest for necklace pod. The moth must be uncommon to Florida. I don’t know how it would have gotten here but maybe there is Necklace pod is also in the legume family so that may be the connection. Necklace pod seeds contain an alkaloid that’s poisonous so maybe the leaves have some too. There appear to be few natural predators (I think the wolf spider is one) for this caterpillar due to the alkaloid absorption. Thank you for your searching and your thoughtfulness in sending the update. Warmly,
Kathleen Scott

Letter 3 – Genista Broom Moth Caterpillars on the Golden Chain Tree

 

Subject:  Caterpillars defoliate Golden Chain Tree
Location:  Mount Washington, Los Angeles, California
Saturday, June 28, 2014 2:33 PM
Several years ago, Mom gave us some tiny seedlings from the Golden Chain Tree,
Laburnum anagyroides, that she has growing in her yard in Ohio.  See GoBotany for images of the Golden Chain Tree.  Well, for many years they have languished, growing very slowly.  Earlier in the week, we noticed brown leaves on the largest one, now grown to about four feet in height.  Caterpillars were feeding on the leaves, skeletonizing them, and spinning loose webs.  We suspect this is some caterpillar in the Ermine Moth superfamily Yponomeutidae, and we thought we might be getting close when we discovered this BugGuide posting of the Laburnum Leaf Miner Moth, Leucoptera laburnella, however our caterpillars seem too big to be Leaf Miners.

What's Eating the Golden Chain Tree???
What’s Eating the Golden Chain Tree???

Some similar looking caterpillars include these Ailanthus Webworm Caterpillars on BugGuide and these Ermine Moth Caterpillars from BugGuide.

Ermine Moth Caterpillars perhaps???
Genista Broom Moth Caterpillars

BINGO!!!  The Scenic Hills Nursery has an image of the Genista Caterpillar, Uresiphita (=Tholeria) reversalis, and according to the site, they are:  “A web producing caterpillar that attacks Texas laurel, crape myrtle, honeysuckle, and Laburnum. Larvae defoliate as well as spin webs.”  Now we realized why it looked so familiar.  We have images of the Genista Broom Moth Caterpillar in our archives and BugGuide has a substantial page devoted to it.

Caterpillars on Golden Chain Tree
Genista Broom Moth Caterpillars on Golden Chain Tree

The Genista Broom Moth Caterpillar is also called the Sophora Worm.

Write if you have an idea what these are.
Genista Broom Moth Caterpillars

 

 

Letter 4 – Genista Broom Caterpillars

 

Subject:  Caterpillars
Geographic location of the bug:  Orange County, ca
August 28, 2017 12:32 PM
I’m wondering what type these are taking over my plants! There are probably 100 on one bush.
How you want your letter signed:  Anna

Genista Broom Caterpillars

Dear Anna,
You can compare your image to this BugGuide image to verify that you are being troubled by Genista Broom Caterpillars,
Uresiphita reversalis, a species sometimes called a Sophora Worm.  Genista Broom Caterpillars feed on leguminous plants.

Letter 5 – Sophora Worm

 

Subject: caterpillar
Location: Bay area
January 8, 2013 1:12 pm
hi buggy
Tons of caterpillars on a flowering bush in Bay area. Has formed nests or webs. thanks for your help I donated $10.00 on paypal.
Signature: Tom

Sophora Worm

Hi Tom,
Thank you for your generous donation.  We don’t like to think that we devote additional time to the identifying submissions if someone has donated to the site, and generally we don’t even know that they have donated.  In light of your extremely generous donation, we have been obsessed with trying to identify your caterpillar.  We are happy you mentioned that the caterpillars formed webs, as that was very helpful.  Knowing the plant upon which the caterpillar or other insect is feeding is usually a tremendous advantage when it comes to identification.  Though we recognized this caterpillar as something we had somewhere in our archives, with nearly 16,000 posts, it is sometimes very difficult for us to find old postings when we cannot remember the name.  We found a match to your caterpillar on the Yard and Garden News of the University of Minnesota Extension website and it was identified as a Genista Broom Moth caterpillar,
Uresiphita reversalis.  The site states:  “An interesting caterpillar has been found apparently for the first time in Minnesota in several areas of the state. A genista broom moth caterpillar, Uresiphita reversalis, is about one inch long when fully grown. It’s a pretty insect with a black head with white markings and a slender yellowish green or mustard colored body. There is a series of black and white colored tubercles (raised spots) running down its body with white hairs coming out of them.  When gardeners have discovered this insect in Minnesota, it has been feeding on false indigo, Baptisia. According to BugGuide this caterpillar has also been reported to feed on “Acacia, Genista, Lupinus, Texas Mountain Laurel (Sophora secundiflora) and other pea family shrubs as well as Crapemyrtle (Lagerstroemia indica) and honeysuckle (Lonicera spp.).”  According to BugGuide, the caterpillar is called a Sophora Worm and this excellent explanation of the common names is provided:  “‘Sophora Worm’ is reference to the native host genus: Sophora.  ‘Genista Broom Moth’ is an odd common name for a native North American moth as Genista (common name of “broom”) is an Old World genus, family Fabaceae.   Numerous species of broom have been introduced into North America, some of which have become noxious invasives such as common broom (Cytisus scoparius), French broom (Genista monspessulana) and Spanish broom (Spartium junceum).”  Once we had the name and family, it was easy enough to locate our own 2005 archival image of a Genista Broom Moth Caterpillar.

hi Daniel
Thank you so much. I think you are too humble! $5 (what the default was for Paypal) is very inexpensive for the service! Don’t sell yourself short. I think there might be a little business in there if you develop the website with a simple drop down menu questionnaire e.g. tents, no tents, geographic area, etc , include picture and ask for $5.
Thanks so much again.
Tom Barnett

Letter 6 – Sophora Worm

 

Subject: Catapillar invasion

Location: Pacifica CA
October 26, 2014 2:42 pm
I have been invaded by hundreds of these catapillars around the outside of my house … Can you please give me some info on these critters – thanks !
Signature: Gina

Genista Broom Caterpillar
Sophora Worm

Hi Gina,
Your caterpillar is known as a Sophora Worm, the larval form of the Genista Broom Moth,
Uresiphita reversalis, and you can verify our identification by viewing this matching image on BugGuideAccording to Bugguide:  “‘Sophora Worm’ is reference to the native host genus: Sophora.  ‘Genista Broom Moth’ is an odd common name for a native North American moth as Genista (common name of ‘broom’) is an Old World genus, family Fabaceae.”  BugGuide also notes:  “Larvae feed on Acacia, Baptisia, Genista, Lupinus, Texas Mountain Laurel (Sophora secundiflora) and other pea family shrubs. Also reported on Crapemyrtle (Lagerstroemia indica) and honeysuckle (Lonicera spp.)” so we are speculating that one of those plants might be growing in your yard.

Letter 7 – Sophora Worm

 

Subject: Caterpillar ID
Location: Las Vegas NV, Mojave Desert
November 6, 2014 4:48 pm
Found about 20 of these caterpillars on a Sweet Broom bush in my yard on November 5, 2014. Please help with ID I am stumped
Signature: P Shaw

Sophora Worm
Sophora Worm

Dear P Shaw,
This is a Sophora Worm or Genista Broom Moth Caterpillar.  They feed on broom and related plants
.

Letter 8 – Sophora Worm

 

Subject: Overcame with bugs
Location: Southeast new mexico
June 5, 2015 6:34 pm
All of a sudden these showed up and within a week how do I get rid of them. In a week they killed a very healthy Spanish broom bush.
Signature: What to do

Genista Broom Moth Caterpillar
Genista Broom Moth Caterpillar

This is a Sophora Worm or Genista Broom Moth Caterpillar, Uresiphita reversalis, and a year ago they defoliated a Golden Chain Tree in our own Los Angeles garden.  The leaves grew back and the tree survived.

Authors

  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

    View all posts
  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

    View all posts
Tags: Genista Caterpillar

Related Posts

13 Comments. Leave new

  • I am on west coast of Florida, Anna Maria Island. Just found quite a few of these on my necklace pod bushes (native florida plant). Cut off affected branches and sprayed with spionsad. Keep watch, it sounds like these could be very destructive.

    Reply
  • We’ve recently discovered some destroying our necklace pod here in the Florida Keys.

    Reply
  • are the Genista caterpillar’s poisonise?

    Reply
  • I live in St. Petersburg, Florida and I just discovered that one of my necklace pod bushes is completely stripped by an infestation of this caterpillar and the other is completely infested as well and I am sure will be completely stripped soon. My question is will this kill the bushes?

    Reply
    • Perennial plants that lose leaves because of a high population of caterpillars should rebound the following year. This is natural and all years do not see the same insect populations. We believe your plants will be fine.

      Reply
  • I also have caterpillars eating all the leaves on my neck lace pods.
    How can I kill them without using toxic poison…..
    Please help

    Reply
  • I also have caterpillars eating all the leaves on my neck lace pods.
    How can I kill them without using toxic poison…..
    Please help

    Reply
  • There is a caterpillar-specific insecticide spray that uses bacterial spores you can spray on necklace pods that are infested. The caterpillar eats the spores and the bacteria grow inside it releasing a mild toxin that does the caterpillar in. Safer makes it as caterpillar killer with BT and you can buy this online. You may have to repeat the spray in 7-10 days

    Reply
  • Thanks for all the help here. I have the cats on my necklace pod in south Broward County, Florida. I didn’t think this plant had any pest issues. This is the first time I’ve noticed these cats, and I’ve had the plant for over 10 years.

    Reply
  • My necklace pod in Miami Dade County has a big infestation of these caterpillars…never seen them before. I have had the plant for many years and have had the Io caterpillar before but it was not nearly as destructive

    Reply
  • I have 2 rather large necklace pod plants and 1 is he’svily covered with these caterpillars. I’ve never seen them before and not sure I like the looks of what they are doing to my plant! Are the moths considered a good thing or maybe kind of invasive? They seem to destroy all the new growth on their host plants.

    Reply

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