Green Stink Bug: All You Need to Know in One Handy Guide

The Green Stink Bug, scientifically known as Chinavia halaris, is a prevalent insect found throughout eastern North America, spanning from Quebec to Florida and even across to the Pacific Coast. They are known for their peculiar, yet recognizable, green shield-like shape and the distinctive foul odor they produce when threatened or crushed. These seemingly harmless insects are not only a nuisance to homeowners but can also be detrimental to various crops and plants, highlighting their significance to both agriculture and ecosystems.

Early spring marks the active period for Green Stink Bugs as they feed on a range of plants, including native and ornamental trees, shrubs, vines, weeds, and soybean. Although they typically prefer wild plant hosts, these bugs often migrate to agricultural fields, such as soybean, causing potential damage to crops. The presence of Green Stink Bugs should not be taken lightly due to their potential negative impact on food crops and ornamental plant life.

What Is a Green Stink Bug

Scientific Classification

• Kingdom: Animalia
• Phylum: Arthropoda
• Class: Insecta
• Order: Hemiptera
• Family: Pentatomidae
• Genus: Chinavia
• Species: Chinavia hilaris (formerly Acrosternum hilare)

Description

The Green Stink Bug is a member of the insect family Pentatomidae. It is also known as Chinavia hilaris. This bug is known for its bright green color and shield-like shape.

These insects are found on various plants, including trees, shrubs, and soybeans. Researchers have found that they prefer wild plants. When such plants mature, the green stink bugs may move to cultivated plants like soybeans.

Physical Characteristics

• Size: Adult green stink bugs grow to be about 12 to 15 mm long.
• Shape: Their body has a shield-like shape, which gives them their distinct appearance.
• Color: They are bright green, with some variations having a brownish shade.
• Wings: The folded wings form an X pattern on their back, which is a characteristic feature.
• Mouthparts: These bugs have piercing mouthparts used for sucking juices from plant tissues.

Green stink bugs are often mistaken for the Southern Green Stink Bug, Nezara viridula. However, the two can be distinguished by the length of their ventral ostiolar canal. The Green Stink Bug has a longer canal that extends well beyond the middle of its supporting plate, while the Southern Green Stink Bug’s canal is shorter.

These bugs are known for their offensive odor, which they release when they feel threatened or are handled. The foul smell is their natural defense mechanism against predators.

Life Cycle and Behavior

Eggs and Nymphs

Green stink bugs begin their life cycle as eggs, which are often laid in clusters of 20-50 on plant surfaces¹. These eggs are:

• One of the largest stink bug eggs
• Pure white with numerous tiny nubs at the crown
• Smooth eggshell surface

Upon hatching, nymphs emerge in five stages called instars². Each stage has unique characteristics:

• Early instars: Small, round, and often black or dark-colored
• Later instars: Closer to adult in shape and coloration

Adults and Mating

Adult green stink bugs are:

• Shield-shaped
• Bright green to dull brown
• 1/2 to 3/4 inch in length and about 1/2 inch wide³

Mating typically occurs in the spring and summer. Males attract females using vibrational signals generated by rubbing their wings against their abdomen⁴.

Molting Process

The molting process is essential for nymphs to transition through the instar stages. Factors affecting molting include:

• Temperature⁵: Warmer conditions often speed up molting rates
• Food availability: Abundant food supply supports successful molts

Comparison Table – Instar Stages vs. Molting

Feeding and Diet

Plants and Fruits

The Green Stink Bug, also known as Chinavia halaris, is a shield-shaped pest known for its offensive odor and feeding habits. This bug feeds on various plants and fruits, causing damage to crops.

• Fruits: Green Stink Bugs have a strong preference for certain fruits, including apples, oranges, peaches, and tomatoes. These pests can cause “catfacing” on peaches due to their feeding, leaving them scarred and deformed.

• Plants: Apart from fruits, Green Stink Bugs also feed on other plants like soybeans and eggplants. Their feeding can cause economic damage to crops as they can affect the yield and quality of the produce.

Seeds and Stems

The Green Stink Bug not only damages fruits and plants, but also targets seeds and stems.

• Seeds: Nuts, cherry pits, and other seeds are also part of the Green Stink Bug’s diet. The bug’s feeding on these parts of the plant can hinder seed development.

• Stems: Another target of this pest is the stems of the plants, such as beans and other crops. By maintaining a wider diet, Green Stink Bugs contribute to troublesome crop and garden damage.

Pest Management and Control

Biological Control

Green stink bugs are a pest that can cause damage to plants. One way to control them is by encouraging the presence of their natural enemies, such as predatory stink bugs.

• Some predatory stink bugs eat other pests like caterpillars, aphids, and larvae
• Spined soldier bugs and anchor bugs are examples of beneficial predatory stink bugs

Encouraging natural predators can be achieved by planting plants that attract them, such as:

• Sunflowers
• Goldenrods
• Marigolds

Another biological control method is the use of pheromones, which can be released to attract and trap green stink bugs.

Chemical Control

Green stink bugs can also be managed using chemical controls. One option is using neem oil, a natural insecticide derived from the neem tree. Some benefits and drawbacks of using neem oil include:

Pros:

• Eco-friendly
• Non-toxic to humans and pets

Cons:

• Might affect beneficial insects
• Needs repeated applications

Other chemical pesticides are available but should be used as a last resort, due to potential harm to the environment and beneficial organisms.

Physical Removal

Physical removal of green stink bugs can help reduce their populations, especially in smaller infestations. One common method is vacuuming.

• Use a hand-held vacuum to remove bugs from plants
• Dispose of the vacuum bag or bugs in a sealed bag to prevent escape

Remember to handle green stink bugs gently, as they release an unpleasant odor when crushed or disturbed.

Relation to Other Stink Bug Species

Brown Marmorated Stink Bug

The Brown Marmorated Stink Bug (BMSB) is a related, but different species from the Green Stink Bug. They share some similarities:

• Both have a shield-like shape
• Both can cause damage to various crops

However, they also have differences:

• BMSB is brown, while Green Stink Bug is green
• BMSB can be more invasive to homes as well as agriculture

Red and Black Stink Bugs

The Red and Black Stink Bugs are another group related to the Green Stink Bug. They share the same shield-like shape, but differ in coloration:

• Red and Black Stink Bugs have distinctive red and black markings
• Green Stink Bug is solid green

Spined Soldier Bug

The Spined Soldier Bug is another stink bug species, but with a unique feature:

• It has distinctive spines on its shoulders

Unlike other stink bugs, the Spined Soldier Bug is a predatory species:

• It is beneficial to agriculture, as it preys on pest insects

Geographical Distribution

Eastern North America

Green Stink Bugs are commonly found in Eastern North America. Their bright green color and shield shape make them easily identifiable. Here’s a list of some characteristics of Green Stink Bugs:

• Bright green color
• Shield shape
• 1/2 to 3/4 inch in length
• 1/2 inch wide

New England to Florida

From New England to Florida, these bugs are prevalent, causing damage to crops and plants in the area. Early spring activity makes them a known presence after winter months.

Below is a comparison of Green Stink Bugs in different locations:

Overall, Green Stink Bugs have a large geographical distribution impacting agriculture and plant life throughout Eastern North America and from New England to Florida.

Economic Importance

The green stink bug, Chinavia hilaris, has significant economic importance, particularly in agriculture. These bugs are known to feed on a variety of plants, causing damage to crucial food crops and reducing yield.

For instance, they are known to attack cotton plants, which leads to a decrease in the quality and quantity of cotton fibers. Similarly, green stink bugs can infest elderberry and black cherry plants, causing damage to the fruit, and making it less appealing for consumption.

• Examples of affected crops:
  • Cotton
  • Elderberry
  • Black cherry

Below is a table comparing their impact on different crops:

In conclusion, the green stink bug causes economic harm by damaging crops and reducing their market value. Ensuring effective pest management is essential for minimizing their impact on the agricultural sector.

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 – Southern Green Stink Bug Nymph

Subject: Bejeweled Bug
Location: West Los Angeles
June 20, 2012 12:55 pm
Hi Bugman,
While trimming our passion Flower vine I spotted this beauty. Can you tell me what it is?
Thx,
Signature: Jeff Bremer

Hi Jeff,
This is a Southern Green Stink Bug nymph, Nezara viridula.  Adults are green and winged.  The Southern Green Stink Bug is believed to be an invasive, exotic species, and according to BugGuide it is:  “a cosmopolitan sp. presumably of African and/or Mediterranean origin.”  BugGuide also indicates:  “highly polyphagous (recorded from hundreds of spp. in >30 plant families), attacking a wide variety of crop plants; especially damaging to new shoots and fruits, including those of soybeans, peas, and cotton.”  Now that you know how destructive they can be, we will admit that the nymphs and adults are quite pretty. 

Letter 2 – Stink Bug nymph from Australia, possibly Green Jewel Bug

What is this bug?
February 1, 2010
Hello bugman,
These interesting and very colorful bugs are all over my house. They seem to be attracted to the white walls of my house. In my front yard I have two bottlebrush trees, one stringy bark gum and some lily pily shrubs. Happy to let the little bug live all over my house….. but i would appreciate a little more info. Regards
Luke
Gold Coast, Queensland, AUSTRALIA.

Good Morning Luke,
This is an immature Stink Bug in the family Pentatomidae.  We believe it may be Lampromicra senator, the Green Jewel Bug, but alas, we are only able to locate images of adult insects.  You may look on the Brisbane Insect Website, or the Save Our Waterways Now website for photos of the adults.  Perhaps someone will write in to confirm this identification, or perhaps provide a link to images of the immature Green Jewel Bug nymph.

Letter 3 – Green Stink Bug

Green Beetle
Whats this BUG? Found in San Mateo, CA. Thanks!
Matt

Hi Matt,
This is not a beetle. It is a Green Stink Bug.

Letter 4 – Green Stink Bug

Seen at the Getty Museum, Los Angeles
Location: Getty Museum, Santa Monica Mountains, southern California, USA
July 12, 2011 3:34 pm
Dear Bugman, this little ”guy” was so cute! I got closer and closer and he just watched me with…eyes, I guess. Are they eyes? What is this thing?
Signature: Salty Cid

Dear Salty Cid,
We were not content to give you the family identification of Stink Bug.  We are relatively certain this is the Green Stink Bug, Chinavia hilaris, based on the range, description and images posted to BugGuide.

Letter 5 – Green Stink Bug Nymph

Yellow, black, orange beetle?
September 11, 2009
Hi,
I am a photographer here in Eastern PA, I go to different National Parks here to photograph insects and others. I found this fellow hanging on a leaf in the dense Nolde Forest here in Reading, PA. After looking online I still can not identify this bug/beetle? Where I found him is was damp and in dense forest. Any ideas?
Monique Francescon
Nolde Forest/ Reading, PA

HI Monique,
We spent a bit of time searching through images on BugGuide, but we are confident we have identified your insect as Acrosternum hilare.  Interestingly, you may find it hard to believe that the common name is the Green Stink Bug.  This is an immature specimen and the coloration is quite variable.  BugGuide also has this disclaimer:  “This is our best interpretation of the BugGuide images based upon Herb Pilcher’s images above. The variation in these images may be because the species is very variable, or it may be that we have images of several different species of Acrosternum here. We put these images on both the genus and the A. hilare species pages since, as a number of people have commented, it is not clear that we yet know how to tell the different Acrosternum species apart.”

Hi!
Thank you for your prompt response! Using the name of the bug you gave me, I looked it up and it appears to be a green stink bug nymph…Very cool and thank you for your help, it is greatly appreciated.
Monique Francescon

Letter 6 – Green Stink Bug Nymph

Can you tell me what kind of beetle this is?
Location:  Massachusetts
July 26, 2010 10:10 pm
Hello- I’ve searched your site for this beetle but I don’t think I’ve seen it. We live in Massachusetts. Thank you for any help you can provide.
Maureen

Hi Maureen,
This is a immature Stink Bug in the family Pentatomidae.  We believe it is a Green Stink Bug, Chinavia hilaris, based on images posted to BugGuide.  True Bugs in the suborder Heteroptera are often confused with Beetles in the order Coleoptera, but beetles have chewing mouthparts and True Bugs have piercing/sucking mouthparts.

Letter 7 – Green Stink Bug Nymph

Green Stink Bug nymph?
Location:  San Jose CA
July 27, 2010 11:50 am
Hi again!
My friend found these little buggers all over her pea plants, and asked me to identify them (being the closest thing to a bug ’expert’ my friends know!). I could tell her that they were true bug nymphs, and that they were up to no good, but I can’t figure out exactly what they are. I read that Green Stink Bug nymphs are highly variable, so perhaps that is why I can’t find a photo to match them. They are pretty small, about an 1/8 inch long.
Do you by any chance recognize them?
BugManDave

Hi BugManDave,
We agree that this looks like a Green Stink Bug Nymph, Chinavia hilaris, though sometimes nymphs are difficult to distinguish from closely related species.  BugGuide illustrates many of the color variations seen in Green Stink Bug Nymphs.

Letter 8 – Green Stink Bug Nymph

Subject: Diminutive Colorful Beetle from the Pacific Northwest
Location: Portland, Oregon
September 22, 2016 1:56 pm
It was a partly cloudy and 67° day when I noticed this colorful beetle moving around nervously on a hibiscus shrub. Its dimensions were about those of a mid to large sized ladybug and an unusually colorful insect for the Portland, Oregon area Thanks for any help you can provide in identifying it and for your wonderful website!
Signature: David

Dear David,
This is not a beetle.  It is a another Stink Bug nymph, and based on this BugGuide image, we have determined it is a Green Stink Bug nymph, Chinavia hilaris.  Here is another image on the Journey to the Center blog.

Dear Daniel,
Thanks for your identification. No wonder I couldn’t find a photo of it — I was looking in the wrong order entirely. I need to start thinking “could it be a nymph?” when I see an unknown insect. The nymph is so snazzy and jewellike, but the adult rather ordinary looking. I’ll try not to “bug” you for a while.
Thanks again,
David

No problem David.  Whenever you get an image of something that you don’t recognize, feel free to send it our way and we will do our best.

Letter 9 – Green Stink Bug Nymph

Subject:  What’s this bug?
Geographic location of the bug:  Hyde Park/Dutchess County, NY
Date: 08/07/2018
Time: 11:23 AM EDT
Your letter to the bugman:  Hello!
I just found this bug in my patch of green beans. Have a market garden and have found a bunch of these bugs.  Can you help me identify and give me any particulars about it? Thanks.
How you want your letter signed:  Lisa Arnoff

Dear Lisa,
This is a Green Stink Bug nymph, Chinavia hilaris, which we identified on BugGuide.  We have gotten several identification requests in the past week, and since your image is especially nice, we will be posting it.  Adult Green Stink Bugs are green, as would be expected, with wings.  According to BugGuide:  “extremely polyphagous: recorded from 20 plant families; adults and older nymphs prefer developing seeds and fruit. May be a pest on soybean, cotton, fruit trees (esp. peach), and many vegetables”

Thank you. Excited to have my photo featured!
Lisa Arnoff

Letter 10 – Green Stink Bug nymph

Subject:  Unknown bug
Geographic location of the bug:  Northern Michigan – Charlevoix
Date: 08/10/2018
Time: 07:19 PM EDT
Your letter to the bugman:  We have never seen this bug. What is it?  Seen 3 in 2 days.
How you want your letter signed:  Tracy

Dear Tracy,
We have been getting numerous requests in the past week to identify Green Stink Bug nymphs, Chinavia hilaris.  According to BugGuide:  “extremely polyphagous: recorded from 20 plant families; adults and older nymphs prefer developing seeds and fruit. May be a pest on soybean, cotton, fruit trees (esp. peach), and many vegetables.”  Your image is really good for identification purposes and nicely illustrates scale.  Here is a BugGuide image for comparison.

Letter 11 – Green Stink Bug Nymph

Subject:  Unidentified Beetle
Geographic location of the bug:  New Jersey
Date: 10/28/2018
Time: 11:29 AM EDT
Your letter to the bugman:  This bug was just walking on our carpet and I thought it would be easy to identify.  Ah, nope.  I have looked at hundreds of pictures and can’t spot it.
It is black, with 2 yellow dots and some small yellow stripes on the tail.  6 legs.
How you want your letter signed:  Lee

Dear Lee,
This is not a beetle.  It is a Green Stink Bug nymph, Chinavia hilaris, and it is pictured on BugGuide. 

Letter 12 – Green Stink Bug nymph from Canada

Subject: Black with yellow stripes
Location: Near Toronto
October 8, 2014 5:45 pm
I found this bug outside my front door and can’t identify it. It is Fall, found it mid day and it is about the size of a dime. I live close to a wooded area just outside of Toronto. Thanks!
Signature: Lindsay

Hi Lindsay,
We followed a lead to the Featured Creatures page on the Green Stink Bug, and though the fifth instar nymph of the Green Stink Bug, Chinavia hilaris, pictured looks similar to your individual, the coloring was not an exact match, but upon checking BugGuide, we did locate several individuals with the colors and pattern of the individual in your image.  According to BugGuide, the Green Stink Bug is “extremely polyphagous: recorded from 20 plant families(5); adults and older nymphs prefer developing seeds and fruit. May be a pest on soybean, cotton, fruit trees (esp. peach), and many vegetables” and it is “the most commonly encountered stink bug in NA”, though that might have been written prior to the spread of the invasive Brown Marmorated Stink Bug.

That’s great, thanks Daniel.

Letter 13 – Green Stink Bug nymphs

Date: 08/04/2018
Subject:  What’s this bug
Date: 08/04/2018
Time: 09:19 PM EDT
Geographic location of the bug:  Ontario
Your letter to the bugman:  Can u please help me identify this bug it is everywhere
How you want your letter signed:  A

Dear A,
This is an aggregation of Green Stink Bug nympsh, Chinavia hilaris.

Letter 14 – Southern Green Stink Bug

Greetings from France
Trying to identify this little fellow, I explored your website and, need I say, enjoyed my tour immensely. A labour of love. A delight. I showed the photo at the Geneva Museum of Natural History (though I live in France, Geneva Switzerland is only a few kilometres away). It was identified as the fifth instar of Nezara viridula, the southern green stink bug, and I was given a handy link: http://creatures.ifas.ufl.edu /veg/bean/southern_green_stink_bug.htm where I read that it is a very common bug, in the US as well as in Europe and elsewhere. Best wishes,
(Mrs) Ira Gardner-Smith
France

Dear Mrs Ira Gardner-Smith,
Thank you for submitting your wonderful image of an immature Southern Green Stink Bug. According to the Featured Creatures link you provided: “The southern green stink bug is believed to have originated in Ethiopia. Its distribution now includes Europe, Asia, Africa and North and South America. In the United States it is known to be found in the southern states of Virginia, Florida, Louisiana, Alabama, Mississippi, Georgia, California, Texas, and Hawaii.”

Letter 15 – Southern Green Stink Bug Nymph

Pretty bug, but good or bad?
These pretty bugs are all over my neglected broccoli, and I’m wondering if they are feeding on the plants or on the aphids. I live in the San Francisco Bay Area. I spent a couple of hours looking at pictures of bugs on the web without finding one that looks like this. Surprising, since the pattern is so distinctive. They’re slightly under a half an inch long, not including legs/antennae.
Ken

Hi Ken,
This is a Southern Green Stink Bug nymph, Nezara viridula. Adults are winged and fly. They have adapted to life in California. BugGuide has information on this species, which is a plant feeder and can do considerable crop damage.

Letter 16 – Southern Green Stink Bug Nymph

Strange Green Bug
Location: Burlingame, California
December 22, 2011 7:00 pm
Just got linked to this site by a friend! I found this bug waiting for me at the top of my basement steps this afternoon, never seen anything like it before! Only one photo came out clearly, but this guy’s only about the size of a dime.
Signature: Marisa

Hi Marisa,
This is an immature Stink Bug.  They are sometimes difficult to properly identify to the species level, but based on a photo posted to BugGuide, we believe this is the nymph of a Southern Green Stink Bug, Nezara viridula.

Letter 17 – Southern Green Stink Bug Nymph

Subject: Ladybug?
Location: Long Beach, CA
May 26, 2017 12:32 am
Hi Bugman,
I’ve tried IDing this beauty but never found it online. After comparing its shape & size, I
think it’s lady bug. Hoping for confirmation. Thanks!
Signature: Sharon in Long Beach

Dear Sharon,
This is NOT a Lady Bug which is actually a beetle.  This is the nymph of a Southern Green Stink Bug, Nezara viridula, an invasive, exotic species that is “cosmopolitan, presumably of African and/or Mediterranean origin” according to BugGuide which also states:  “highly polyphagous (recorded from hundreds of spp. in >30 plant families), attacking a wide variety of crop plants; especially damaging to new shoots and fruits, including those of soybeans, peas, and cotton.”

Oh noooo! Thanks for the quick update and I love the site! Always go there first.

Letter 18 – Southern Green Stink Bug Nymphs

Subject: Black Lady Bug-like Bug w Yellow Spots?
Location: Northeast Los Angeles
May 15, 2017 9:20 pm
Hello-
Found these critters clustering on my Arroyo Azul Sage and Clarkia today, here in northeast Los Angeles. I assumed lady bugs, but upon closer inspection, thought not. Ribbed shell too weird, etc. Harlequin bugs? Help!
Signature: David N

Dear David,
Nymphs can be difficult to identify, but we are confident we have correctly identified these Southern Green Stink Bug nymphs, , thanks to an image that led us to Featured Creatures where we learned:  “The southern green stink bug is believed to have originated in Ethiopia. Its distribution now includes the tropical and subtropical regions of Europe, Asia, Africa and the Americas. In South America, it is expanding its range to Paraguay, south Argentina and toward the north-east of Brazil, due to expanding soybean production (Panizzi 2008). In North America, it is limited primarily to the southeastern United States, Virginia to Florida in the east, Ohio and Arkansas in the midwest, and to Texas in the southwest. It is also established in Hawaii and California (Capinera 2001).”  Based on images posted there, these are third instar nymphs.  According to BugGuide:  “highly polyphagous (recorded from hundreds of spp. in >30 plant families), attacking a wide variety of crop plants; especially damaging to new shoots and fruits, including those of soybeans, peas, and cotton.”  Since sage is often considered a natural insect repellent, we were surprised to learn that this species is not affected by the strong oils found in sage.  Since they feed by piercing the plant and sucking fluids, we would recommend hand picking them to remove them.  Can you be more specific about your location?  Our offices are in Mount Washington.

Letter 19 – Spined Green Stink Bug Nymph

Bug ID
Could you identify this bug for me? Central Florida, December, it is about an inch to inch-and-half long anf flat. Thanks
Ken Pichon

Hi Ken,
This is an immature Stink Bug in the family Pentatomidae. We are curious as to the large size, so we tried to identify the species on BugGuide. We found several photos of the adult Spined Green Stink Bug, Loxa flavicollis, which is found in Florida. There is also mention of another member in the same genus, Loxa viridis, but no image. As BugGuide does not show any immature specimens, we are not sure if the spines are only present on the adults. We will try to do additional research, including contacting Eric Eaton. If this is a member of the genus Loxa, we are requesting your permission to post the image to BugGuide as well. Here is Eric’s input: “It is a stinkbug nymph, have no idea what genus or species. Florida has so many more species than the rest of the U.S., including more introduced, exotic species, that I can’t help much with many of the Florida insect IDs. Please try Julieta Brambila, though, as the Heteroptera (Hemiptera) are her specialty, and she is IN Florida. Eric”

Permission granted. Thank you for your help. I look forward to hearing of any new information.
Ken

Dear Daniel,
Happy Holidays! I have forwarded the image to the pentatomid expert Joe Eger. Let’s wait for his answer. I only have one reference specimen of an immature of Loxa, and it definitely does not reach one inch, but looks similiar to the photo, though not in color since the photograph is of a live insect. Nice photo. We’ll see what Joe says. Thanks,
Julieta
Here is Joe’s answer. “Feliz Navidad a day late. I agree that this thing looks like Loxa. It looks like a pretty mature nymph so the size is not too far off. I can be pretty certain that this is Loxa sp. – May be L. flavicollis or L. viridis – I can’t separate nymphs.”

Letter 20 – Spined Green Stink Bug Nymph

Leaf/Lime Bug!
February 2, 2010
This bug that’s about 1 1/2 cm in diameter has been on my garage wall for at least 30 hrs. It seems to be alive and resting. When I first saw it I thought it was a small leaf. When I enlarged the picture, it looks like a lime!
Marion Furlong
Port Charlotte, Florida

Hi Marion,
This is an immature Spined Green Stink Bug  in the genus Loxa.  In December 2006 we received a very detailed image of a nymph and we requested assistance from Eric Eaton who put us in touch with Julieta Brambila, who contacted an expert in Stink Bugs named Joe Eger who made the identification.  There are two possible species, Loxa flavicolis and Loxa viridis which are difficult to distinguish from one another as nymphs.  You may read about that identification in our archives and you may see images of the adults on BugGuide.  The thoracic spines that appear on the adult are not evident on the nymphs.  What most amazes us is that this same individual has been living on your garage for thirty years and it has never matured.  We found the Global Biodiversity Information Facility website that indicates the range of Loxa flavicolis as being Florida, Texas, Mexico and Central America, but we are not having any luck identifying the host plants.  The Sonoran Desert Bugs website provides some information.

Correction
Hi Danial,
Thanks for your time and help identifying the bug as a Spined green stink bug, I was pleased to hear from you so fast and to be a part of your bug identification site.
When I read what you printed about the bug being on my garage for 30 years I thought I’d made a mistake. You misread it, it had been there for 30 hours! I thought you may like to know so you can change it.
If it’s not to late, it’s still there and has moved into a different position. I took a couple more pictures from a different angle and with my fingers next to it to get an idea of the size.
Thanks again for your help.
Marion Furlong

Oops.  Thanks for the correction Marion.  Sometimes we read things too quickly.