Monday, February 19, 2007

 

Has the Feared Nopal Moth Arrived in Mexico?

 

By Allan Wall

 

On Valentine’s Day, 2007, Hector Sanchez, the Mexican government’s plant and crop safety director, announced that the nopal moth has probably reached Mexico.  For decades Mexican officials have been concerned about this possibility, which endangers a Mexican national symbol and could affect the livelihoods of thousands of Mexican farmers and their families. 

 

The nopal is a group of New World cactus plants, with a flat-leaf, also called the prickly pear.  Various types of nopal grow throughout the Western Hemisphere, with one form being the most cold resistant of cacti and it grows in northern Canada.

 

There are 100 species of nopal in Mexico, the most famous and economically valuable being the Opuntia ficus-indica species, along with similar members of the Opuntia subgenus.  

 

The Opuntia ficus-indica nopal is a symbol of Mexico.  The Mexican flag and coat of arms both feature an eagle, with a serpent in his beak, perched upon a nopal cactus.

 

The nopal is a food source and staple of the Mexican diet.  Like the tortilla, it is remarkably flexible.  In fact, part of the nopal is considered a fruit and part is regarded as a vegetable. Nopal can be served fresh, canned or dried, in various forms: with eggs (huevos con nopales), in taco form (tacos de nopales), in soups or with shrimp.  Nopal is rich in vitamins (A, C, B6 and riboflavin) and minerals (magnesium, potassium, manganese, copper and iron).

 

Nopal has medicinal uses, it has been utilized as a binding and waterproofing agent in the production of adobe, and it is a host for cochineal insects that produce dyes, food coloring and cosmetics.

 

The Mexican nopal has a world-girdling history.  In the 16th century sailors introduced it to the Old World, where the Opuntia ficus-indica plant adapted easily to Africa and the Mediterranean basin. It adapted so well that some people thought it was native to the Mediterranean. It’s commercially grown in Sicily and Algeria, and the “sabra” cactus of Israel, regarded as the symbol of the native-born Israeli, is really a Mexican ficus-india nopal.

 

The nemesis of the nopal, the nopal moth, Cactoblastis cactorum, also known as the “cactus moth,” is native to southern South America.  The larvae stage of this insect devours the inside of the cactus. 

 

In the 1920s the moth was taken to Australia to control the nopal, which had been previously introduced and had gotten out of hand.  The nopal moth did its job Down Under, greatly reducing the presence of nopal in Australia.  

 

Following the Australian example, the nopal moth was taken to South Africa and then to the Caribbean, where it was used to destroy nopal plants on land which farmers wanted to use for other crops.

 

The use of Cactoblastis cactorum as a biological control agent made perfect sense in these other countries. But in Mexico nopal is grown as a crop, and a valuable one at that. Approximately 50,000 Mexican families make their living from nopal, with crops worth about US$100 million in the aggregate.

 

So the nopal moth could do a lot of damage in Mexico, which is why authorities have dreaded its potential arrival for years. In fact, just two years ago, in 2005, Hector Sanchez publicly warned of this danger.

 

And in January of 2007, six moths were captured in Cancun that look like the dreaded Cactoblastis cactorum. 

 

Since the nopal moths are already in the Caribbean, it wasn’t too hard for them to arrive on Isla Mujeres, an island off the northeast coast of Yucatan near Cancun.  They could have been blown there in a hurricane, or unintentionally brought by a visitor.  The moths could have flown themselves from Isla Mujeres to Cancun, or perched on an unsuspecting tourist riding a cross-strait ferry.

 

The suspicious moth has been sent to the United States for testing, where U.S. Department of Agriculture (USDA) entomologist Alma Solis, even before testing, said the photographs appear to be of Cactoblastis cactorum.  The United States has also had problems with a nopal moth infestation from the Caribbean.

 

In the meantime Isla Mujeres and Cancun are being searched for infected nopal.

 

No matter what the outcome of these tests, the danger of the nopal moth to Mexico’s nopal is a constant threat.  As Hector Sanchez put it, “We may be able to eradicate this outbreak, but unfortunately, just as it came this time, it could come again.”

 

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Allan Wall, a MexiData.info columnist, recently returned from a tour of duty in Iraq.  He currently resides in Mexico, where he has lived since 1991. He can be reached via e-mail at allan39@prodigy.net.mx.