By Matt Gibson
Also known as goldbugs, or golden lady bugs, golden tortoise beetles are a common garden pest that chew through the leaves of various plants, especially morning glory vines and sweet potato vines. Despite their destructive nature, golden tortoise beetles are actually rather handsome bugs. They are about one-fourth of an inch long, and vary from dark-orange to metallic gold in color.
When they are not stressed, tortoise beetles tend to be shiny and gold. When stressed, they turn dark-orange, or red, often with black or red designs on their backs, and the metallic element fades into a glossy-looking exterior. Tortoise beetles can shift their color at will also, to match the shade of the leaves they are feeding on. They do this in order to blend into their surroundings. They look a little bit like ladybugs, but they are not closely related, despite the resemblance.
Golden tortoise beetles live off of the leaves of many common garden plants, chewing through them and destroying the ornamental value of their host plants, dutifully leaving behind chewed up foliage wherever they go. Thankfully, tortoise beetles are never around in large enough groups to inflict serious damage on your crops, so in the vast majority of cases you can simply ignore them and enjoy their cool look.
Tortoise beetles have several built-in defensive features that work to keep them safe from predators. Their wings have developed hard outer-shells which help them to grip tightly to the surface of a leaf. These wing shells, or covers, also hide the bug’s appendages, like a tortoise. Without arms or legs to grasp onto, these hard-shelled creatures are a challenge for predators.
The larvae of the tortoise beetle, which has a dark head and a brown, yellow, or green body, has its own unique defensive mechanism to deter predators. Tortoise beetle larvae can paste together discarded skin and feces with debris, to form what is called an anal fork, which is held over the back half of the insect’s body, shielding its most vulnerable areas from attack.
Identifying Golden Tortoise Beetles
Golden tortoise beetles can be almost entirely gold-colored, red, or reddish-orange. It can have black or red markings on its back. Tortoise beetles have a dome-shaped body, similar to that of a ladybug, but when they are disturbed or frightened, they can flatten out their bodies, drawing closer to the leaf surface and covering all of their appendages, similar to the way a tortoise will hide from predators by going inside its shell.
The golden sheen of the tortoise beetle is eye-catching, rather attractive, and can be dulled, or altered at will by changing the moisture level near the surface of its nearly translucent skin. The tortoise beetle changes colors in order to blend in with its surroundings to hide from predators. The metallic-gold or gold-red insect can dull its metallic sheen, turning from gold or red to a dull brown or green to hide in the foliage of the plant it is feeding on. When the tortoise beetle dies, the metallic gold color dies with it, leaving a dull brown corpse.
The Life Cycle of the Golden Tortoise Beetle
The life cycle of the golden tortoise beetle takes approximately 40 days to develop from an egg into an adult beetle. Tortoise beetles are present all throughout the eastern United States, spreading west to about the middle of the country, as far as Iowa and Texas. There is not a wealth of biological knowledge about the tortoise beetle, most likely because the damage that they inflict on crops is primarily ornamental, and has little to no economic impact.
The white, oval, flattened eggs of the golden tortoise beetle can be found attached on the bottom of leaves or along the stems of host plants in clusters of around 20. The tiny, 1 mm long eggs hatch in just five to ten days.
The larvae of the tortoise beetle is quite unique-looking. The larvae are thick, but flattened and covered in spiny branch-like arms that jut out in every direction along the center of the larvae. The larvae are yellow, red, brown, or reddish-brown, with dark heads. Using its old skin casts and fecal matter, the tortoise beetle larvae glues them together and creates a protective structure known as an anal fork. The skin, debris, and feces shield is held in place over the hard to defend back region of the larvae’s body to keep predators from attacking them directly. Golden tortoise beetle larvae will mature somewhere between 14 and 21 days time.
Once the larvae has matured, it attaches itself to the foliage of the host plant by its anal end, then pupates. Pupae are generally brown, with spines just like the larvae. Also like the larval form of the golden tortoise beetle, the pupae still carry around the anal fork made of fecal matter, old skin, and debris made during the larval period. Pupae grow to five to eight mm long, developing from pupae to adult in just seven to 14 days.
Adult beetles are relatively small, clocking in at five to seven millimeters long. Adult beetles can be different colors, but are typically either orange, reddish-orange, or gold metallic. The head and the appendages of the adult tortoise beetles are hidden for the most part, by the outer shell. After a week or two, the adults emerge and begin feeding during the last few weeks of summer.
Which Garden Plants Do Golden Tortoise Beetles Eat?
Mainly linked to the sweet potato vine and its relatives, plants like morning glory, and bindweed. Only plants from the sweet potato family, also known as the Convolvulaceae family, can be host plants. However, if you are having a problem with tortoise beetles, do not just remove all of your morning glory vines and sweet potatoes. Once tortoise beetles are in your garden, they will find leaves to feed on, even if their favorites are ripped up. Tortoise beetles also enjoy the foliage of zinnias, mallows, cabbage, milkweed, eggplant, strawberry, raspberry, and corn plants.
How To Get Rid Of Golden Tortoise Beetles
Though chemical pesticides are a quick fix for golden tortoise beetles and many other garden pests, they often do more harm than good. Chemical pesticides can also harm the beneficial insects that are present in your garden’s ecosystem. Beneficial insects, like bees, parasitic wasps, ladybugs, are essential parts of a thriving garden, responsible for pollinating the crops, and preventing garden pests.
Long term exposure to chemical pesticides can be harmful to humans as well, increasing the risks of Parkinson’s disease, depression, and low sperm count. Excessive pesticide usage allows harmful chemicals to enter the water table, wreak havoc on the ecosystem, and taint our produce with neurotoxins. The most eco-friendly way to prevent garden pests is to find organic methods for preventing and controlling pest problems.
Preventative tactics, such as keeping your garden free of weeds, and making sure your plants are well-fed and well-watered, will go a long way towards deterring pests. Removing the golden tortoise beetles by hand and crushing them is the most effective treatment option and the quickest and easiest way to handle small infestations.
Another safe organic treatment that will deter tortoise beetles is a homemade neem oil spray treatment. If there are too many beetles for you to keep up with picking them off by hand, a diluted neem oil spray may be the best answer. Simply mix two tablespoons of neem oil and one tablespoon of dish soap with one gallon of water. Use a spray bottle to apply the mixture to areas where you see clusters of golden tortoise beetles, shaking the bottle occasionally to keep the oil from separating in the bottle.
Continue to treat affected areas for three to five straight days or until the pests are gone. Spray the neem oil mixture on vines, stems and leaves, but try to avoid spraying directly on flowers so as not to drive away pollinators. Use the spray late in the evening when bees are less active and when the sun is not around to dry the solution up too quickly.
Though insecticides are only recommended for the most extreme infestations and are rarely necessary, larvae and adult golden tortoise beetles are easily killed by spraying residual insecticides, like permethrin, directly onto the leaves of affected plants.
There are several natural enemies of the golden tortoise beetle that can be released to combat the pest in particularly difficult infestations to avoid the use of commercial insecticides. There are two insects that are known to attack adult golden tortoise beetles, a wasp known as Burks (Tetrastichus cassidus) and the Aldrich fly (Eucelatoriopsis dimmocki). The tortoise beetle larvae’s skin and poop shield defense system known as the anal fork is no match for insects with long piercing-sucking mouthparts, and only really defends the larvae from small predators with efficiency. Damsel bugs, shield bugs, assassin bugs, and several species of ladybird beetle can all be effectively used to kill golden tortoise beetle larvae.
If you are seeing a golden tortoise beetle for the first time, take a little bit of time to study the specimen up close. If it is all metallic gold, it is feeling calm and well. If it becomes stressed by sudden environmental change, it will shift colors. During dry weather periods, it’s metallic lustre will fade into an orange-bronze iridescence. Golden tortoise beetles can appear gold, red, brown, orange, bronze, and even green, and can be shiny, metallic, iridescent, translucent, or dull. Many also have black or red markings on their backs as well. They are actually really neat once you take a few minutes to study them. It is a shame that they have to feed on the foliage of some of today’s most commonly grown garden plants.