The Cactus Moth Detection and Monitoring Network (CMDMN)
The Cactus moth (Cactoblastis cactorum
Berg.) is a widely used biological control agent of pricklypear cactus
in Australia and South Africa. Cactus moth appeared in the Florida Keys in 1989, spreading as far as South
Carolina and Louisiana. Cactus moth quickly destroys a stand of pricklypear, and is a threat to natural
biodiversity, horticulture, and forage in the southwestern United States and Mexico.
Blue = Pricklypear locations - Red = Cactus Moth locations
Concerned about the potential damage caused by the cactus moth, a partnership has been formed between
federal agencies (USGS BRD, USDA APHIS), state agencies (states' Departments of Agriculture), universities
(Mississippi State University) Cooperative Extension Service, and other interested groups to monitor the
distribution of the cactus moth. This partnership developed the Cactus Moth Detection and Monitoring Network,
composed of volunteer monitors from public and private land management units, garden clubs and Master
Gardeners to monitor the spread of the moth. The program relies on volunteers to monitor cactus populations
and report observations. This is the first step of an Early Detection and Rapid Response (EDRR) approach.
The data will be used to support modeling efforts to better predict likely locations for new pricklypear
cactus and cactus moth, helping guide surveys.
Negative Cactus Locations
The CMDMN is storing several different types of information about pricklypear cactus and the cactus moth.
Some of this information is provided graphically through a GIS application. The system displays the locations
of pricklypear cacti with the moth sightings included. Negative reports are also being used for modeling
In the effort to monitor the progress of the cactus moth, sentinel sites have been established along
the leading edge. These sites are monitor on a regular basis for the presence of the cactus moth.
Scientific Name: Cactoblastis cactorum
(Berg) (Insecta: Lepidoptera: Pyralidae)
Australia, Hawaii, India, South Africa, and the Caribbean
The southeastern U.S. and threatens Mexico
Pricklypear cacti ( Opuntia
Total destruction of plant
Adult moths can fly (distance unknown). Storm (hurricane) winds can
carry adults. Investations can spread by consumers through nurserys and by transplanting from one area to another.
Rangeland grazing, nursery plants and landscaping, production of fruits, pads,
and cochineal dyes for human use, desert ecosystems and biodiversity, human welfare and economy of the
southwestern U.S. and Mexico.
Originally from Argentina, Cactoblastis
was found to be one of the most successful biological control
agents in history. After being introduced into Australia in the 1920s, the cactus moth drastically reduced
the exotic and invasive pricklypear cacti. For Australia, control of the Opuntia
populations was a necessity
in order to convert large areas of land back to agriculture.
For similar controls, the moth was introduced in India (year uncertain), South
Africa in 1933, and Hawaii in 1950. Then in 1956, the cactus moth was introduced to the Caribbean island of Nevis
from where it spread to the other islands. Eventually, the invader was detected in the Florida Keys in 1989, and
may have been introduced as a hitchhiker on ornamental cacti imported from one of the Caribbean islands. Today,
free-living populations are found as far north as Bull Island, South Carolina along the Atlantic Coast and as
far west as east Louisiana along the Gulf Coast. It appears that cactus moth populations are
concentrated on barrier islands and coastal areas of the Atlantic and Gulf Coasts.
Ironically, what was a control agent has become an invasive species that threatens native and endemic
pricklypears as well as the cactus industry and desert ecosystems of the Southwest and Mexico. The
cactus moth in the United States, directly threatens a total of 31 species of native pricklypear
cacti plus numerous other native species associated with cacti. In Mexico, 53 species of pricklypear
are threatened, including 38 endemic species.
The female moth lays eggs stacked on top of
each other like pancakes to form an "egg stick" that resembles a cactus spine. Each female can
lay 60-100 eggs
in a single egg stick and can lay 200-300 eggs
few days. Egg sticks are about an inch long and are usually on the undersides or other protected parts
of the plant pads. The egg stage lasts 3-4 weeks. The caterpillars burrow into a pad after hatching and
feed together as a group. The infestation by the lightly colored young larvae may be difficult to detect
without splitting the pad open.
As the larvae mature, frass and sap may be pushed out of openings in the pad and onto the ground. Eventually
the pad will become transparent and hollow. Larvae may move to additional pads to complete development,
especially if the initially infested pad is small. Larvae mature in 4-5 weeks. Mature larvae leave the plant
and pupate under dead leaves or between the pads where they spin white cocoons. The pupal stage lasts 15-20
days. They emerge as adult moths and the cycle starts over.
Symptoms of internal feeding on pricklypear can be seen at anytime of the year, however, larvae may be
difficult to find during the colder months. Larvae tend to congregate in the lower parts of the plant
and are not seen feeding in galleries when it is cold. If daytime temperatures reach a certain point,
larvae will migrate to the upper cactus pads, and even sometimes be seen on the exterior of the pad on
the sunny side of the plant.
In Argentina, Australia, and South Africa, Cactoblastis
normally undergoes two generations per year. However, on
the U.S Gulf Coast, the cactus moth has been observed having three generations per year. The extra generation is
contributed to the warmer climte. Adult flight and mating periods are as follows:
- 1st flight period - late March through May
- 2nd flight period - July through August
- 3rd flight period - late September through mid-November
Monitoring visually for adults is not suggested, but this generational information will assist
with knowing approximate time periods in which to expect to see fresh egg-sticks and subsequent
larval feeding within the cactus plants.
In the wake of the Cactoblastis
, only death and destruction are found, presenting a threat to human welfare and
The pricklypear cactus is a cultural icon in Mexico where its image is on the Mexican flag and coins. Pricklypears
are commonly relied upon as food as the fruit are processed into jam and syrup while the plant itself
is commonly boiled or pickled. The cactus has its place in the pharmaceutical market as well as cattle fodder
mainly during the dry years. Cactus is a $50 million to $100 million a year industry in Mexico. In the U.S.,
it is estimated that pricklypear cactus has a trade, nursery, landscape, crop, and forage value of up to
$70 million a year, mainly in the Southwest. Environmentally, cacti prevent erosion and are a habitat and
food source for many species of invertebrate, birds, mammals and other animals.
Pricklypear cactus is an important plant resource to the U.S. nursery and landscape industry. The growth
of xeriscape landscape design in high population growth areas such as Phoenix and Tucson, Arizona, and Las
Vegas,Nevada, has been
promoted by state and local governments. In Arizona alone, the ornamental pricklypear cactus industry
encompasses over half a million plants with a wholesale and retail value estimated to be more than $15 million.
Other impacts on the economic effects can be found in a
USDA-PPQ white paper
Infestation by Cactoblastis
may be indicated by the presence of egg-sticks, which resemble cactus
spines. However, native cactus-feeding Lepidoptera lay similar egg sticks that currently cannot be
distinguished reliably from those of the cactus moth. Identification has to wait until the larvae appear.
The mature larvae are more distinct with a characteristic orange to red color interrupted by dark banding or
spots on the body and are relatively easy to distinguish from those of native species. However, younger stages
are similar to those of native species and the two sometimes have been misidentified. Available
larval identification keys are limited to differences in color of mature larvae. Also, records of some
species may only be known from limited reference material. If you suspect the presence of the cactus moth,
please view important information below.
The adult cactus moths are non-descript brownish-gray moths that can only be definitively identified
by a microscopic examination of dissected male genitalia, although the native species differ from Cactoblastis
in having a more plumose antenna. Click on the moth image to the right for a comparison between the native
. High resolution images are also provided for
They generally appear as typical pyralid
moths with pronounced labial palps of the female, thus the name "snout moths". The forewings show a
characteristic banding pattern, however other related Phycitinae have similar banding. If you suspect the presence of the cactus moth,
please view important information below.
Additional Help for Identification
For more information and a key to the cactus feeding species in the Southeastern US, see:
Solis, M. Alma, Stephen D. Hight, and Doria 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 46(1) 2-3.
Do you suspect the presence of the cactus moth?
Knowing where the cactus moth are located is critical in the efforts to monitor and control its spread. Please
do not disregard the importance of proper notification and identification.
If you suspect your pricklypear
cactus is infested by the cactus moth, please notify
Dr. Victor Maddox and Dr. Richard Brown
State University. Dr. Maddox will collect information about your cactus species and Dr. Brown will perform
the identifications on insect samples that are submitted.
Insect samples should be prepared before shipping. Larvae encountered on pricklypear should be
collected, killed in boiling water, and preserved in 70% ethyl alcohol or by following specific instructions
from Dr. Brown. These should be sent, with all collection information and any digital photos, to Dr. Richard
Brown (contact information below). Information about confirmed infestations will be provided to appropriate
state and federal officials who will determine a proper course of action for addressing the problem.
Dr. Brown is also interested in receiving specimens of any Lepidoptera found on pricklypear in the U.S.,
including different stages, accompanied by adults reared out from larval collections. Digital photos of
live larvae will also be helpful in documenting color variations and providing future visual keys to surveyors.
Dr. Richard Brown, Director
Mississippi Entomological Museum
Box 9775 (103 Clay Lyle for FEDEX/UPS)
Mississippi State, MS 39762
Phone: 662-325-2085 Email: email@example.com
The generic name Opuntia is often applied to a related group
called "cholla" cactus (pronounced "choya"), which now are placed in a separate genus known as Cylindropuntia.
In older taxonomic treatments, you will see Opuntia divided into two subgenera, Platyopuntia, with a pad-like
form, and Cylindropuntia, with a cane-like form.
Pricklypear cacti belong to the Cactaceae Family and the Genus Opuntia
. In the United States, it is a large
genus of cacti with approximately 93 species. The genus Opuntia
consists of all pricklypear cacti, those
having flat-pad stem forms, or cladodes.
The list of known hosts for Cactoblastis cactorum
(the cactus moth) are pricklypear
cactus species, in the genus Opuntia
, with the exception of a few records from one species in the related
. While other host records appear in the literature, none of these records of the cactus moth
attacking any other cactus species are reliable. Cylindropuntia
are not thought to be hosts.
Another related genus, Grusonia
, appears in older literature as Opuntia
, but species in that genus are also
not known to be hosts. Images are available
to help the identification of some of the most common Opuntia
species within the southeastern U.S. See the table below for a list of all native Opuntia species (within the
group). Many ornamental species found in nurseries or used in landscaping are native but, others
may be from Mexico or South America. (Naturalized indicated by *)
Images to help identify the most common species within the southeastern U.S.
engelmannii (Cow's Tongue)
humifusa - on bedrock
(pads are more elongated)
pusilla - in fruit
pusilla - spine/fruit closeup
pusilla - in flower
pusilla - with dark winter coloration
pusilla - with dark winter coloration
stricta - showing growth habit
stricta - in fruit
To prevent further spread of cactus moth in the U.S., it is very
important to detect, report and rapidly respond to all new outbreaks of the pest. The first priority
must be to make a serious attempt to eradicate such infestations.
Be aware there are a number of native species of Lepidoptera larvae that can be found feeding on pricklypear
and may be confused with Cactoblastis cactorum
. These native species are not considered a threat
to the pricklypear population. Correct identification by a qualified entomologist is important. Please refer to
the Identification section
for what to do if you suspect a cactus moth infestation.
Sterile insect release technology and other control methods are being developed and tested by the USDA
Agriculture Research Service and other groups. Effective control of the cactus moth using insecticides is
still in the testing phase and is proving difficult. Since the larvae spends most of its time within the
cactus pad, insecticides are having little effect. Confirmed infestations should be eradicated by manual
removal and destruction of egg-sticks and infected cacti stems.
Invasive species are a significant problem for terrestrial and aquatic ecosystems in the United States, degrading
their biodiversity and the ecosystem services they provide to our society. Despite this, little attention has been
directed to this significant problem until the last decade, when federal and state governments and
nongovernmental organizations alike have suddenly become painfully aware of this burgeoning problem.
While the awareness of the problem has been widespread, the reaction to this threat has not been uniform, and
tools to deal with these problems are restricted. In particular, response within the Mid-South states lags behind
that of other regions where more resources have been allocated towards dealing with invasive species.
Mississippi State University is developing and implementing a program of planned research, extension, and
regional coordination to address these needs. Our approach is multidisciplinary, and involves biologists,
ecologists, computer scientists, economists, engineers, and others acting together as a research team.
Graduate and summer student opportunities are available. Students interested in educational opportunities
should view the Invasive Species Program Poster
for more information, or send a general inquiry to:
Dr. John D. Madsen
Box 9652, Mississippi State, MS 39762-9652
Ph: 662-325-2428, Fax: 662-325-7692
The ability to monitor the spread of the cactus moth entirely rests on knowing where cacti are located.
Information is urgently needed on locations where native and ornamental varieties of cacti are known to
occur in the Mid-South. Information on cactus locations can be sent to
Dr. Victor Maddox
. Cactus plants that are within 30 meters of
one another are considered the same population. Information that is needed on each cactus population is as
- Physical Address (or the best of one you can provide)
- GPS Location of Cactus
- Land Use (Natural, Residential, Commercial, Agricultural, Nursery)
- Ownership (Private, Local, County, State, Federal Agency)
- Contact Person for the Population (Name, Address, Phone)
- Species of Cactus (if not known, please provide good digital photos)
- Approximate Number of Plants
- Size of Population Area (# acres, # sqft)
- Do You Suspect the Cactus Moth is Present?
Assistance is also needed from individuals who can volunteer to monitor stands of native cacti and ornamental
cacti for presence of the cactus moth along the southern portions of Alabama, Mississippi, Louisiana, and
If you are interested in volunteering, providing cactus information, or just for more information on how
you can help, please contact:
Dr. Victor Madddox
Box 9555, Mississippi State, MS 39762-9555
- Cactus Moth Survey Manual
- Information about collecting survey information for cactus locations, visual observations for the
cactus moth, and trap monitoring stations.
- Cactus Moth Detection Network Fact Sheet
- Fact sheet on the Early Detection and Reporting of Cactus Moth in the U.S.
- Cactus Moth Brochure
- A tri-fold brochure on the cactus moth used as handouts in information packets.
- Opuntia Handout
- A handout used to inform the public of the need to locate populations of Opuntia Cacti and describes how
the public can help in that effort.
Our major partners are U.S. Geological Survey Biological Resources Division (USGS BRD)
U.S. Department of Agriculture Animal and Plant Health Inspection
Service Plant Protection and Quarantine (USDA APHIS PPQ)
. Please visit the
USDA APHIS PPQ Cactoblastis
website for more information about the overall cactus moth program.
(Cactus moth and Opuntia resources from our partners will be
listed under Resources.)
USDA-APHIS has a volunteer coordinator in the Gulf Coast area, and there are USDA Pest Survey Specialists
that cover various regions of the U.S. conducting surveys for various pests. If you need personal assistance,
please contact Joel Floyd or go to the following URL to obtain contact information for the Pest Survey
Specialists covering your area.
John D. Madsen, Ph.D.
Mississippi State University
Mississippi State, MS 39762-9652
ph. 662-325-2428 fax 662-325-7692
Victor Maddox, Ph.D.
Mississippi State, MS 39762-9555
Cactus Moth Identification
Richard L. Brown, Ph.D.
Department of Entomology & Plant Pathology
Box 9775 (103 Clay Lyle for FEDEX/UPS)
Mississippi State, MS 39762-9775
Web Database System, Webmaster
Mississippi State, MS 39762-9652
Coordinator for Federal, Public,
and Private Convseravtion Lands
Randy G. Westbrooks, Ph.D.
USGS BRD - National Wetlands Research Center
233 Border Belt Drive
Whiteville, NC 28472