The Colorado potato beetle (Leptinotarsa decemlineata; also known as the Colorado beetle, the ten-striped spearman, the ten-lined potato beetle, and the potato bug) is a beetle known for being a major pest of potato crops. It is about long, with a bright yellow/orange body and five bold brown stripes along the length of each of its wings. Native to the Rocky Mountains, it spread rapidly in potato crops across the United States and then Europe from 1859 onwards.
The Colorado potato beetle was first observed in 1811 by Thomas Nuttall and was formally described in 1824 by American entomologist Thomas Say. The beetles are orange-yellow in color with 10 characteristic black stripes on their front wings or elytra. The specific name decemlineata, meaning "ten-lined", derives from this feature.
Adult beetles may be visually confused with L. juncta, which is the false potato beetle. Unlike the Colorado potato beetle, it is not an agricultural pest. L. juncta also has alternating black and white strips on its back, but one of the white strips in the center of each wing cover is missing and replaced by a light brown strip.
Larvae
The orange-pink larvae have a large, 9-segmented abdomen, black head, and prominent spiracles, and may measure up to in length in their final instar stage.
The beetle larva has four instar stages. The head remains black throughout these stages, but the pronotum changes color from black in first- and second-instar larvae to having an orange-brown edge in its third-instar. In fourth-instar larvae, about half the pronotum is colored light brown. This tribe is characterized within the subfamily by round to oval-shaped convex bodies, which are usually brightly colored, simple claws which separate at the base, open cavities behind the procoxae, and a variable apical segment of the maxillary palp.
Its first association with the potato plant (Solanum tuberosum) was not made until about 1859, when it began destroying potato crops in the region of Omaha, Nebraska. Its spread eastward was rapid, at an average distance of 140 km per year. The beetle has the potential to spread to temperate areas of East Asia, India, South America, Africa, New Zealand and Australia.
Human interaction
By 1874 it had reached the Atlantic Coast.
These controls proved ineffective, as the beetle soon reached Europe. In 1877 L. decemlineata reached the United Kingdom and was first recorded from Liverpool docks, but it did not become established. Many further outbreaks have occurred; the species has been eradicated in the UK at least 163 times. The last major outbreak was in 1977. It remains as a notifiable quarantine pest in the United Kingdom and is monitored by the Plant Health and Seeds Inspectorate of the Animal and Plant Health Agency (APHA) to prevent it from becoming established. A cost-benefit analysis from 1981 suggested that the cost of the measures used to exclude L. decemlineata from the UK was less than the likely costs of control if it became established. In July 2023 Colorado beetles were officially confirmed in a potato field in Kent, England. Farmers and growers, gardeners and members of the public were being encouraged to remain vigilant for signs of the pest and to report potential sightings to APHA. In January 2026 it was reported that beetle had once again been eradicated from the UK.
Elsewhere in Europe the beetle became established near USA military bases in Bordeaux during or immediately following World War I and had proceeded to spread by the beginning of World War II to Belgium, the Netherlands and Spain. The population increased dramatically during and immediately following World War II and spread eastward, and the beetle is now found over much of the continent. After World War II, in the Soviet occupation zone of Germany, almost half of all potato fields were infested by the beetle by 1950. In East Germany they were known as Amikäfer ('Yankee beetles') following a governmental claim that the beetles were dropped by American planes. In the European Union it remains a regulated (quarantine) pest for the Republic of Ireland, Balearic Islands, Cyprus, Malta and southern parts of Sweden and Finland. It is not established in any of these member states, but occasional infestations can occur when, for example, wind blows adults from Russia to Finland.
<gallery heights="180px" mode="packed">
File:kartoffelkaefer fg01e.jpg|Native range of the potato and native and current range of the Colorado beetle
File:Propagation du doryphore en Amérique du Nord.svg|Expansion of the Colorado potato beetle's range in North America, 1859–1876
File:Doryphore - expansion en Europe.svg|Expansion of the Colorado potato beetle's range in Europe, 1921–1964
</gallery>
Lifecycle
Colorado potato beetle females are very prolific and are capable of laying over 500 eggs in a 4- to 5-week period. The eggs are yellow to orange, and are about long. They are usually deposited in batches of about 30 eggs on the underside of host leaves. Development of all life stages depends on temperature.
After 4–15 days, the eggs hatch into reddish-brown larvae with humped backs and two rows of dark brown spots, one row on each side. They feed on the leaves of their host plants. Larvae progress through four distinct growth stages (instars). First instars measure about long, and the last (fourth) instars about long. The first through third instars each last about 2–3 days; the fourth lasts 4–7 days.
Upon reaching full size, each fourth instar spends several days as a nonfeeding prepupa, which can be recognized by its inactivity and lighter coloration. The prepupae drop to the soil and burrow to a depth of several inches, then pupate. In some locations, three or more generations may occur each growing season. When shown colored boards, the beetles had a positive response between 45° and 0° in terms of mean angular directions (MADs). In the article Sexual contact influences orientation to plant attractant in Colorado potato beetle, Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae) by Joseph Dickens, the beetles were attracted to kairomone substance but after mating, their attraction to it reduced. Within 24 hours of mating, there was no difference between levels of attraction to kairomone and control solvent.
Enemies
thumb|[[Coleomegilla maculata preying upon Colorado beetle eggs]]
At least 13 insect genera, three spider families, one phalangid (Opiliones), and one mite have been recorded as either generalist or specialized predators of the varying stages of L. decemlineata. These include the ground beetle Lebia grandis, the coccinellid beetles Coleomegilla maculata and Hippodamia convergens, the shield bugs Perillus bioculatus and Podisus maculiventris, various species of the lacewing genus Chrysopa, the wasp genus Polistes, and the damsel bug genus Nabis.
The predatory ground beetle L. grandis is a predator of both the eggs and larvae of L. decemlineata, and its larvae are parasitoids of the pupae. An adult L. grandis may consume up to 23 eggs or 3.3 larvae in a single day.
In a laboratory experiment, Podisus maculiventris was used as a predatory threat to female L. decemlineata specimens, resulting in the production of unviable trophic eggs alongside viable ones; this response to a predator ensured that additional food was available for newly hatched offspring to increase their survival rate. The same experiment also demonstrated the cannibalism of unhatched eggs by newly hatched L. decemlineata larvae as an antipredator response.
{| class="wikitable" style="margin-left: auto; margin-right: auto; border: none;"
|+ Examples of parasitoids, predators, and pathogens of different life stages of Leptinotarsa decemlineata
! Type !! Species !! Order !! Predates !! Location !! Reference
|-
! Parasitoid
| Chrysomelobia labidomerae
| Acari
| Adults
| USA, Mexico
|
|-
!
| Edovum puttleri
| Hymenoptera
| Eggs
| USA, Mexico, Colombia
|
|-
|-
!
| Anaphes flavipes
| Hymenoptera
| Eggs
| USA
|
|-
!
| Myiopharus aberrans
| Diptera
| Eggs
| USA
|
|-
!
| Myiopharus doryphorae
| Diptera
| Larvae
| USA, Canada
|
|-
!
| Meigenia mutabilis
| Diptera
| Larvae
| Russia
|
|-
!
| Megaselia rufipes
| Diptera
| Adults
| Germany
|
|-
!
| Heterorhabditis bacteriophora
| Nematoda
| Adults
| Cosmopolitan
|
|-
!
| Heterorhabditis heliothidis
| Nematoda
| Adults
| Cosmopolitan
|
|-
! Predator
| Lebia grandis
| Coleoptera
| Eggs, Larvae, Adults
| USA
|
|-
!
| Hippodamia convergens
| Coleoptera
| Eggs, Larvae
| USA, Mexico
|
|-
!
| Euthyrhynchus floridanus
| Hemiptera
| Larvae
| USA
|
|-
!
| Oplomus dichrous
| Hemiptera
| Eggs, Larvae
| USA, Mexico
|
|-
!
| Perillus bioculatus
| Hemiptera
| Eggs, Larvae, Adults
| USA, Mexico, Canada
|
|-
!
| Podisus maculiventris
| Hemiptera
| Larvae
| USA
|
|-
!
| Pselliopus cinctus
| Hemiptera
| Larvae
| USA
|
|-
!
| Sinea diadema
| Hemiptera
| Larvae
| USA
|
|-
!
| Stiretrus anchorago
| Hemiptera
| Larvae
| USA, Mexico
|
|-
! Pathogen
| Bacillus thuringiensis <br />subsp. tenebrionis
| Bacillales
| Larvae
| USA, Canada, Europe
|
|-
!
| Photorhabdus luminescens
| Enterobacterales
| Adults, Larvae
| Cosmopolitan
|
|-
!
| Spiroplasma
| Entomoplasmatales
| Adults, Larvae
| North America, Europe
|
|-
!
| Beauveria bassiana
| Hypocreales
| Adults, Larvae
| USA
|
|-
|}
Sexual dimorphism
Colorado potato beetles exhibit sexual dimorphism. In particular, they exhibit dimorphism in the adhesive tarsal setae. The paper "Sexual dimorphism in the attachment ability of the Colorado potato beetle Leptinotarsa decemlineata (Coleoptera: Chrysomelidae) to rough substrates" by Voigt demonstrates this dimorphism. The setae, hair-like structures, in males is to help them adhere to the females' elytra when mating. Colorado potato beetles also have adhesive setae that allows them to attach to host plants. Additional mitochondrial DNA sequencing showed two haplotypes in the Columbia Basin compared to places like Wisconsin showed seven haplotypes.
Reasoning behind the genetic diversity is the landscapes of the regions: shrub-land and grains in the Columbia Basin versus the forest, corn, and beans in the Central Sands. In the same study, potatoes covered 3.5% in the Columbia Basin and 1.8% in the Central Sands.
Genetic differentiation in the Colorado potato beetle can be impacted by agricultural practices such as crop rotation. The same study mentioned earlier examines crop rotation's effects on genetic differentiation in Colorado potato beetles that were not found in the Central Sands. On the other hand, genetic diversity decreased with increased crop rotation in the Columbia Basin. Three haplotypes were shared in the populations and all others were restricted to a single population in North America. 51 European beetles collected from eight populations yielded in one haplotype that was also fixed in the Idaho population. Transposons are sequences of genetic material that can shift/move their place within an organism's genome, and 17% of the Colorado Potato beetles’ genome consists of transposable elements. In order for dispersal to occur, certain conditions need to be met, both abiotic and biotic.
Abiotic conditions
Abiotic factors include temperature, photoperiod, insolation, wind, and gravity. A soil temperature of 9 °C causes soiled beetles to move up. They emerge when soil surface temperature is 14–15 °C.
Potato crop pest
Around 1840, L. decemlineata adopted the cultivated potato into its host range and it rapidly became a most destructive pest of potato crops. It is today considered to be the most important insect defoliator of potatoes. Larvae may consume 40 cm<sup>2</sup> of potato leaves during the entire larval stage, but adults are capable of consuming 10 cm<sup>2</sup> of foliage per day.
The economic cost of insecticide resistance is significant, but published data on the subject are minimal. In 1994, total costs of the insecticide and crop losses in the US state of Michigan were $13.3 million, representing 13.7% of the total value of the crop. The estimate of the cost implication of insecticides and crop losses per hectare is $138–368. Long-term increased cost to the Michigan potato industry caused by insecticide resistance in Colorado potato beetle was estimated at $0.9 to $1.4 million each year.
Potato protection
thumb|A Colorado beetle larva eating a leaf of a potato plant
Colorado potato beetles pose significant dangers to potatoes, which are a quintessential agricultural crop. In response to the damage they do, some potatoes have been genetically modified to resist attack and damage from the beetles. Specifically, the Russet Burbank Potato. The insertion of a cryIIIA gene that codes for the insect control protein Bacillus thuringiensis var. Tenebrionis is the method that was used. Insecticides remain the main method of pest control on commercial farms. However, many chemicals are often unsuccessful when used against this pest because of the beetle's ability to rapidly develop insecticide resistance. Different populations in different geographic regions have, between them, developed resistance to all major classes of insecticide, although not every population is resistant to every chemical. The mechanisms used include improved metabolism of the chemicals, reduced sensitivity of target sites, less penetration and greater excretion of the pesticides, and some changes in the behavior of the beetles.
Nonpesticidal management
thumb|right|East German [[Ernst Thälmann Pioneer Organisation|Young Pioneers collecting beetles during the war against the potato beetle]]
Bacterial insecticides can be effective if application is targeted towards the vulnerable early-instar larvae. Two strains of the bacterium Bacillus thuringiensis produce toxins that kill the larvae.
Beauveria bassiana (Hyphomycetes) is a pathogenic fungus that infects a wide range of insect species, including the Colorado potato beetle. It has shown to be particularly effective as a biological pesticide for L. decemlineata when used in combination with B. thuringiensis.
Crop rotation is, however, the most important cultural control of L. decemlineata.
Other cultural controls may be used in combination with crop rotation: Mulching the potato crop with straw early in the growing season may reduce the beetle's ability to locate potato fields, and the mulch creates an environment that favors beetle's predators; Plastic-lined trenches have been used as pitfall traps to catch the beetles as they move toward a field of potatoes in the spring, exploiting their inability to fly immediately after emergence; flamethrowers may also be used to kill the beetles when they are visible at the top of the plant's foliage.
Biological management
Some potential sources of control for the Colorado golden beetle is the eulophid egg parasitoid Edovum puttleri. This parasitoid can kill more than 80% of beetle eggs. It does it by parasitization, probing, and host feeding. Edovum specializes in the Colorado potato beetle, which gives it easier access to the eggs it eats. This parasitoid tolerates warmer temperatures than the beetle. Researchers found that immigrating adult beetles had almost no spatial dependence in any covariance-based treatment, while larval immigrant populations developed the highest densities in field centers. Results imply that perimeter tactics employed by Colorado Potato beetles can give valuable insight into site-specific resistance management programs to optimize insecticide usage. A widespread campaign was launched against the beetles; posters were put up and school children were mobilized to gather the pests and kill them in benzene or spirit.]]
L. decemlineata is an iconic species and has been used as an image on stamps because of its association with the recent history of both North America and Europe. For example, in 1956, Romania issued a set of four stamps calling attention to the campaign against insect pests, and it was featured on a 1967 stamp issued in Austria. The beetle also appeared on stamps issued in Benin, Tanzania, the United Arab Emirates, and Mozambique.
In popular culture
Neapolitan mandolins (also called Italian mandolins) are often called tater bugs, a nickname given by American luthier Orville Gibson, because the shape and stripes of the different color wood strips resemble the back of the Colorado beetle.
The fans of Alemannia Aachen carry the nickname "Kartoffelkäfer", from the German name for the Colorado beetle, because of striped yellow-black jerseys of the team.
During the 2014 pro-Russian unrest in Ukraine, the word , from the Ukrainian and Russian term for Colorado beetle (, ), gained popularity among Ukrainians as a derogatory term to describe pro-Russian separatists in the Donetsk and Luhansk Oblasts (provinces) of Eastern Ukraine. The nickname reflects the similarity of black and orange stripes on St. George's ribbons worn by many of the separatists.
In some European cultures, the Colorado potato beetle is known as the 'gourd beetle' due to the likeness of the beetle to various gourds of the Cucurbitaceae family.
Notes
:1.For a more comprehensive list of natural predators, pathogens and parasitoids, see here.
References
External links
- PotatoBeetle.org
- Polish Film Chronicle: Fight against Colorado Beetle