The prickly pear moth (Cactoblastis cactorum) is a moth that preys specifically on cactus species. It has been introduced in various locations around the globe to provide biological control of invasive cacti species...
The prickly pear moth (Cactoblastis cactorum) is a moth that preys specifically on cactus species. It has been introduced in various locations around the globe to provide biological control of invasive cacti species and has proved itself as a successful biocontrol agent in Australia, South Africa and some Caribbean islands. However, from the Caribbean it spread into Florida and has attacked non-target cacti species. It is feared that it will cause large scale losses of native cacti diversity in North America and possibly have a large economic, social and ecological impact in Opuntia rich areas of southwestern USA and Mexico.
Females of Cactoblastis cactorum have a wingspan of 27-40mm, whilst male wingspan is slightly smaller (23-32mm). The adult is fawn with faint dark dots and lines on the wings. It normally rests with its wings wrapped around its body. The forewings are greyish brown but whiter toward the costal margin. Distinct black antemedial and subterminal lines are present. Hindwings are white, semihyaline at base, smoky brown on outer half with a dark line along the posterior margin. The average longevity of the adult is 9 days. The incubation period of eggs depends on temperature; the shortest time being 18 days. The eggs usually hatch in 23-28 days. Larvae are gregarious in nature, initially pinkish cream coloured, with black red dots on the back of each segment. Later instars become orange and the dots coalesce to become a dark band across each segment reaching up to 1.5cm. The pupa is enclosed in a fine white silk cocoon which consists of a loose outer covering and a more compact inner cocoon. Pupation sites are usually found among debris of rotting cladodes under stones, logs, bark and just beneath the surface of the soil. The average length of the pupal period is 21-28 days. (Jordan Golubov., pers. comm., 2005).
Native range: South America (Zimmermann et al. 2000). Northern provinces of Argentina (Entre Rios, Corrientes, Santa Fe, northern portion of Cordoba, Santiago del Estero, Tucuman, Salta, Jujuy and the Chaco), in Uruguay (along the Uruguay and Plata Rivers from Piriapolis in the south and north to Salta) and Paraguay (Villa de Concepcion and vicinities of Asuncion), also in the southern portions of Brazil (Matto Grosso at Corumba but may include Rio Grande do Sul and Santa Catarina). (Jordan Golubov., pers. comm., 2005)
Known introduced range: Africa, Asia, Australasia-Pacific region and North America (Stiling, 2002). After its earlier success as a biocontrol agent in Australia and South Africa, it was introduced into the Caribbean in 1957 to manage weedy native cactus species. The moth gradually spread throughout the Caribbean Islands and was first detected in south Florida on Big Pine Key in 1989 (Bloem and Bloem, 2012).
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
On hatching, all larvae from one eggstick enter the plant at one point. They tunnel freely within the cladodes, consuming the whole of the interior except the vascular bundles and leaving the undamaged cuticle as a transparent tissue. Burrowing activity usually causes secondary bacterial activity which hastens the destruction of cladodes. When one cladode has been eaten or decayed, the larvae may penetrate into the next segment. During this process the colony usually divides into two or more groups. Adults have no functional mouthparts and emerge only to reproduce (Jordan Golubov., pers. comm., 2005).
Oviposition is normally at dusk or early dawn and may be responding to carbon dioxide concentrations around pads (Stange, 1997; Stange et al 1995). The number of eggs in a stick varies greatly but the average contain from 76-90 eggs. Each female can deposit several eggsticks; 3-4 but can frequently lay 8-12. In Australia, mating takes place during the early morning hours and copulation has never been documented at night, or after 2100hrs. Adults normally remain inactive during daylight hours. In South Africa, sexual activity is found on the first and second night after adult emergence. In Florida, peak periods of sexual activity begin between nautical and civil twilight and ends before sunrise (for a detailed behavioural sequence of sexual activity see Hight et al. 2003)
When fully grown the larvae exit the cladodes and individually drop to the ground and find pupation sites, usually in the debris of rotting cladodes (Jordan Golubov., pers. comm., 2005).
Introduction pathways to new locations Biological control:Cactoblastis cactorum was introduced to St Kitts, Nevis and Montserrat in the Caribbean (Pemberton, 1995). Natural dispersal:Cactoblastis cactorum in the Florida Keys may have been the result of the moth naturally dispersing across the Caribbean, or it may have been introduced unintentionally on horticultural prickly pear cacti imported into Florida (Solis et al. 2004) Nursery trade:Cactoblastis cactorum in the Florida Keys may have been the result of the moth naturally dispersing across the Caribbean, or it may have been introduced unintentionally on horticultural prickly pear cacti imported into Florida (Solis et al. 2004)
Original text compiled by IUCN SSC Invasive Species Specialist Group (ISSG)
Cactoblastis cactorum threatens Opuntia species both native and cultivated. Opuntia species are important in subsistence and commercial agriculture. They also have ecological importance – they can prevent desertification and promote reforestation in arid areas through their ability to survive scarce or erratic rainfall and high temperatures (IAEA, 2002). There is concern that C. cactorum will invade the cactus-rich desert areas of South-Western USA and Mexico. Nearly all Opuntia are at risk of attack by C. cactorum; Cylindropuntia or ‘chollas’ (once included in the genus Opuntia but now seen as taxonomically separate) are not preferred hosts (Bloem and Bloem, 2012).
Stiling (2002) states that, "Cactoblastis cactorum oviposits by gluing sticks of about 50-90 eggs on cactus spines. The gregarious larvae bore into the pads or cladodes, devouring them from the inside. About four pads are needed for the development of the larvae from a complete egg stick." The authors also report that, "There are at least 31 species of prickly pear in the US that are likely to be attacked by C. cactorum and 56 species in Mexico. As well as the threat to wild cacti, there are over 250,000ha of Opuntia plantations in Mexico that support a thriving agricultural industry, most of which is centred on harvesting fruits or pads."
Stiling (2002) reports that: “As well as its commercial value, Opuntia is used by a whole community of organisms (109 species of invertebrates, 9 species of reptiles, 54 mammals and 25 species of birds)". (Vigueras and Portillo, 2001; Mellink and Rojas-Lopez, 2002).
In a study of Opuntia along the west coast of Florida, overall survival of cacti over a 6-year period was found to be high (~75%). Nevertheless, juvenile mortality is thought to be high and C. cactorum should still be considered a threat to Opuntia in the USA and Mexico, particularly for rare opuntioids (Jezorek et al., 2012; Stiling and Moon, 2001). For example C. cactorum threatens the rare cactus O. corallicola, known from just a few islands in Florida (Stiling, 2010; Stiling and Moon, 2001).
Cactoblastis cactorum is a voracious feeder on cacti in the genus Opuntia (prickly pear cacti) and is an example of a successful weed biological control programme. It was introduced from Argentina into Australia in the mid 1920's for the biological control of invasive and non-native Opuntia. C. cactorum was then intentionally spread from Australia into other countries with prickly pear problems (Solis et al. 2004).
Cactoblatis cactorum are in the subfamily Phycitinae (family Pyralidae). Phycitine adults are often similar to each other; however, genitalia can provide positive identification (Habeck and Bennet, 2002, Heinrich, 1939).
Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.
Original text compiled by the IUCN SSC Invasive Species Specialist Group (ISSG)
In South Africa, Cactoblastis cactorum is controlled in commercial Opuntia ficus-indica stands by removing the conspicuous egg sticks from the plant (Zimmerman et al. 2000). Stiling (2002) suggests that this may be an effective method of reducing damage to Mexican Opuntia plantations, should C. cactorum arrive there, but not in the wild where manual removal is difficult.
In Florida Opuntia plants were protected by cages as soon as C. cactorum was discovered. However, cages prevent cross-pollination and are subject to toppling over in the tropical storms and hurricanes that frequent South Florida. When the cages topple they can knock over and kill the cacti inside. In 1999, all the cages were removed before a hurricane arrived and they were not reinstalled. Instead, a team of four trained volunteers was assigned to identify C. cactorum egg sticks and remove them from the O. corallicola plants. The team made weekly visits to the cacti (Stiling, 2002). Solis et al. (2004) report that, "The Nature Conservancy has tried to protect cacti by physically removing the egg sticks."
Scientists with USDA Center for Medical, Agricultural and Veterinary Entomology in Tallahassee (Florida), and Crop Protection and Management Research Unit in Tifton (Georgia), looked into ways of monitoring the distribution and spread of this insect, and evaluated different trap designs and attributes to develop the best moth trap. Bloem et al. (2005) state "The trap that worked the best in attracting and catching male cactus moths was a standard, insect, wing trap that is unpainted, placed above ground at a height of 2 metres, and baited with four, newly emerged, female cactus moths. This trap is being developed to determine the cactus moth's distribution and to organize control efforts".
Leibee and Osborne (2001) report that "Working in Africa, Pretorius & Van Ark (1992) evaluated stem injections of mevinphos, dimethoate, and monocrotophos against C. cactorum. Stem injection of mevinphos, dimethoate, and monocrotophos was unpromising. However good protection against larval attack was achieved with cover sprays of the same insecticides. A cover spray of cypermethin gave complete protection against larval attack. A cover spray of cypermethrin mixed with chlorpyrifos was very effective against cactus moth and Dactylopius opuntiae. Chlorpyrifos alone was also effective against both insects. Carbaryl gave poor to excellent control." The authors also report that several of the insecticides studied are not registered in the U.S.
Mahr (2001) states that, "Biological control of C. cactorum would, on the surface, seem to be an ironic but logical solution. Several natural enemies of C. cactorum are known, but a thorough search through its large native range has not been conducted. Most of the known natural enemies are generalists and therefore pose potential risk to several native pyralid moths that use Opuntia throughout North America." Pemberton and Cordo (2001) report that, "The primary risk of employing biological control is the reduction of the many North American cactus moths, some of which probably regulate native Opuntia that can be weedy. Biological control probably can reduce the abundance of C. cactorum populations but is unlikely to prevent the spread of the moth. The relative benefits and risks of biological control need to be carefully assessed prior to any operational biological control programs."
Stiling (2002) states that, "In South America, there are at least eight to nine common species of parasitoids including one braconid larval parasitoid, five to six ichneumonid wasps, and a tachinid fly. The braconid wasp, Apanteles alexanderi, can cause more than 30% larval parasitism. While these parasitoid species may be able to lessen the amount of damage to cacti by C. cactorum, it is unlikely they could prevent damage entirely or stop its spread. Also, if the parasitoids did become abundant, it is possible they might spread back to the Caribbean, lessening the abundance of C. cactorum there, and undoing the successful biocontrol effects on pest cacti."
In South Africa Robertson (1988) has documented predation of C. cactorum eggs by native ants, and monkeys have been seen to consume larvae from pads in South Africa.
Scientists with USDA-ARS Center for Medical, Agricultural and Veterinary Entomology in Tallahassee, FL and Crop Protection and Management Research Unit in Tifton conducted a field-cage study (Hight et al. 2005) using the 'Sterile Insect Technique' (SIT). They observe that the Sterile Insect Technique (SIT) could be one method that may stop the moth and perhaps push back its leading edge. The authors state "Results of the study suggest that an overflooding ratio as low as 5:1 can effectively suppress C. cactorum in field-cages, and that releasing both genders together is more effective than releasing males only. Finally, the dispersal ability of C. cactorum is not significantly affected by treating the adults with gamma radiation".
Since 2007, in collaboration with the scientists at Tallahassee and Tifton, the USDA-ARS-South American Biological Control Laboratory in Argentina has been conducting additional studies on the ecology and biology of Cactoblastis cactorum. A survey of natural enemies was conducted and the distribution of the cactus moth and the Opuntia host plants were assessed. Four haplotypes of the moth were found (Marsico et al., 2011); preliminary results suggested that each haplotype utilizes a different Opuntia sp. as host. Among natural enemies, the most promising candidate for biocontrol is the gregarious larval parasitoid Apanteles n. sp. (Brachonidae), still under study. This wasp was misidentified as A. alexanderi, which seems to be restricted to other Pyralidae cactus moth. Several ecological studies on the host cacti and the natural enemies are in progress.
Habeck, D. H., and K. A. Bennett. 2002. Cactoblastis cactorum (Berg) (Insecta: Lepidoptera: Pyralidae). Featured Creatures: University of Florida Institute of Food and Agricultural Sciences
Heinrich, C. 1939. The cactus feeding Phycitinae: a contribution toward a revision of the American Pyralidoid moths of the family Phycitidae. Proceedings of the National Museum Smithsonian Institution 86: 331-413.
Hight, S. D., J. E. Carpenter, K. A. Bloem, S. Bloem, R. W. Pemberton, and P. Stiling. 2002. Expanding Geographic Range of Cactoblastis cactorum (Lepidoptera: Pyralidae) In North America. Florida Entomologist 85(3): 527-529.
Hight, S. D., S. Bloem, K. A. Bloem, and J. A. Carpenter. 2003. Cactoblastis cactorum (Lepidoptera: Pyralidae): observations of courtship and mating behaviors at two locations on the Gulf coast of Florida. Florida Entomologist 86: 400-408.
International Atomic Energy Agency (IAEA)., 2002. Mitigating the Threat of Cactoblastis cactorum to International Agriculture and Ecological Systems and Biodiversity: Report and Recommendations of a Consultants’ Group Meeting organized by the Technical Co-operation Department of the IAEA and the Joint FAO/IAEA Division of Nuclear Applications in Food and Agriculture, Vienna, Austria, July 2002. http://tc.iaea.org/tcweb/abouttc/strategy/thematic/pdf/reports/Thematic_plan_cactus.pdf
Johnson, D. M, and D. S. Stiling. 1998. Distribution and dispersal of Cactoblastis cactorum (Lepidoptera: Pyralidae), and exotic opuntia-feeding moth. Florida Entomologist 81(1): 12-21.
Leibee, G. L., and L. S. Osborne. 2001. Chemical control of Cactoblastis cactorum (Lepidoptera: Pyralidae). Florida Entomologist 84(4): 510-513.
Mahr, D. L. 2001. Cactoblastis cactorum (Lepidoptera: Pyralidae) in Noth America. A Workshop of Assessment and Planning. Florida Entomologist 84(4): 465-474.
Mann, J. 1969. Cactus feeding insects and mites. Bulletin 256. Smithsonian Institution Press. Washington D. C., USA
Mellink, E., and M. Rojas-Lopez. 2002. Consumption of Platyopuntias by wild vertebrates. In P. Nobel (ed) Cacti: Biology and Uses. Island Press, pages 109-123. California, USA.
Pemberton, R. W. 1995. Cactoblastis cactorum (Lepidoptera:Pyralidae) in the United States. An Immigrant biological control agent or an introduction of the nursery industry. American Entomology 41: 230-232.
Pemberton, R. W., and H. A. Cordo. 2001. Potential and risks of biological control of Cactoblastis cactorum (Lepidoptera: Pyralidae) In North America. Florida Entomologist 84(4).
Pettey, F. W. 1948. The biological control of prickly pear in South Africa. Sci. Bull. Dept of Agri. Union of South Africa 271: 1-163.
Robertson, H. G. 1988. Spatial and temporal patterns of predation by ants on eggs of Cactoblastis cactorum. Ecological Entomology 13: 207-214.
Soberon, J., J. Golubov, and J. Sarukhan. 2001. The Importance of Opuntia in Mexico and routes of invasion and impact of Cactoblastis cactorum (Lepidoptera: Pyralidae). Florida Entomologist 84(4).
Solis, M. A., D. H. Stemphen, and D. R. Gordon. 2004. Tracking the Cactus Moth, Cactoblastis cactorum Berg., as it flies and eats its way westward in the U.S. News of the Lepidopterists' Society.
Stange, G. 1997. Effects of changes in atmospheric carbon dioxide on the location of host by the moth Cactoblastis cactorum. Oecologia 110: 539-545.
Stange, G., Monro, J., Stowe, S., and Osmond, C. B. 1995. the CO2 sense of the moth Cactoblastis cactorum and its probable role in the biological control of the CAM plant Opuntia stricta. Oecologia 102: 341-352
Stiling, P. 2002. Potential non-target effects of a biological control agent, prickly pear moth, Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae), in North America, and possible management actions. Biological Invasions 4: 273-281, 2002.
Zimmermann, H. G.; V. C. Moran; J. H. Hoffmann., 2000. The renowned Cactus Moth, Cactoblastis cactorum: Its Natural History and Threat to Native Opuntia floras in Mexico and the United States of America. Diversity and Distributions, Vol. 6, No. 5. (Sep., 2000), pp. 259-269.
Reviewed by: Dr. Jordan K. Golubov Profesor-Investigador Titular C Lab. Sistematica y Ecologia Vegetal Departamento El Hombre y Su Ambiente Universidad Autonoma Metropolitana -- Xochimilco Mexico
Principal sources: Stiling, 2002. Potential non-target effects of a biological control agent, prickly pear moth, Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae), in North America, and possible management actions. Biological Invasions 4: 273-281
Compiled by: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG)