Practical information to identify and manage non-native, invasive plants and animals
The Quiet Invasion:
A Guide to Invasive Species of the Galveston Bay Area
Cactus moth
Cactoblastis cactorum

ITIS TSN:117641
Presence:Species of Concern
Habitat:Terrestrial
Native Range:South America
Human Health
This species poses no known human health impacts.
Prohibited Lists
The USDA along with some state governments has established quarantine areas to prohibit the interstate movement of cactus moth host material (Opuntia sp. cactus -- nursery stock and fresh plant parts used in food products) out of states where the species is known to exist (see geographic distribution below) (USDA 2009a).
Introduction Pathways
The cactus moth was first introduced to Australia in the 1920s as a biological control for prickly pear cactus. Later, the cactus moth was introduced to the Caribbean Islands and was first reported in the U.S. in the Florida Keys in 1989 where it may have hitchhiked in on ornamental cacti from the Caribbean (MSU 2009).
Geographic Distribution
As of 2010, this species is not reported in Texas. Infestations are reported in South Carolina, Georgia, Florida, Alabama, and Mississippi (five-state federal quarantine area). This moth is generally thought to be moving west along the Gulf Coast where the prickly pear cactus (Opuntia sp.) is found.
Specific Primary Habitats
The cactus moth requires prickly pear cactus as a host plant to complete its life cycle. It is therefore found in habitats where prickly pear cactus occur (pasture lands, coastal upland habitats, arid and semiarid lands).
Ecological, Economic, or Social Impact
Cactus moth larvae feed on and can destroy large stands of prickly pear cacti. Through the loss of Opuntia cacti, the cactus moth threatens native habitats and agriculture. Prickly pear is a source of food for birds and wildlife and represents a major plant genus of desert ecosystems in the southwestern U.S. and Mexico. Prickly pear cacti are prized as culinary ingredients in Latin American cuisine (e.g. nopales) and are used in the manufacture of cosmetics, dyes, and indigenous medicines. The cacti also provides ecosystem services related to rangeland grazing, hunting, tourism, and religious/cultural activities.
Physical Description
Cactus moth infestation is evidenced by damage to the infested cactus in the form of yellowing of plant tissue, oozing of plant fluids and deposition of insect frass on the ground below plant (a powdery mixture of insect fecal matter and plant material) (Floyd 2007). Adult cactus moths are nondescript gray-brown moths with faint dark dots and wavy lines on the wings. Larvae are found inside the cactus leaves as caterpillars that are pinkish-cream colored, becoming orange with age. Black and red dots on the dorsal surface of each body segment combine to form dark bands which overlay the orange, giving the larvae a distinctive orange and black banding pattern (SMS 2007).
Reproduction Characteristics
Females release pheromones in the early morning hours to attract males. Males respond and mating proceeds for a short time. After a period of internal incubation, females cement a stick-like chain of 70-90 eggs to cactus spines (Floyd 2007; SMS 2007). After several weeks, the eggs hatch and larvae burrow into the cactus pad where they develop.
Feeding
Cactus moth larvae have been found to eat most Opuntia cactus species with flat pads (SMS 2007). Caterpillars (larvae) develop en masse inside the pads of the cactus by feeding on the internal tissue of the plant; eventually hollowing out and destroying the cactus pad. Mature larvae exit the cactus pad to form white cocoons under leaf litter on the ground at the base of the cactus, in crevices of nearby trees, or in other nearby protected places. After emergence, adult moths disperse to new areas to begin the life cycle again.
Control
Since early detection is key to preventing the spread and establishment of this species, regional/local monitoring or surveillance is essential. Prickly pear cacti should not be imported from quarantine areas. Moth-infested cacti should be carefully removed (avoid injury from cactus spines).

This species belongs to the following lists:
Images
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Eggs of the cactus moth (<i>C. cactorum</i>). Photo courtesy Susan Ellis, USDA APHIS PPQ, Bugwood.org.
Eggs of the cactus moth (C. cactorum). Photo courtesy Susan Ellis, USDA APHIS PPQ, Bugwood.org.
Adult cactus moth (<i>C. cactorum</i>). Photo courtesy Susan Ellis, USDA APHIS PPQ, Bugwood.org.
Adult cactus moth (C. cactorum). Photo courtesy Susan Ellis, USDA APHIS PPQ, Bugwood.org.
Larvae of the cactus moth (<i>C. cactorum</i>) on a prickly pear cactus. Photo courtesy Ignacio Baez, USDA Agricultural Research Service, Bugwood.org
Larvae of the cactus moth (C. cactorum) on a prickly pear cactus. Photo courtesy Ignacio Baez, USDA Agricultural Research Service, Bugwood.org
Page Updated/Reviewed: 08/31/2010 2:06 PM
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