Mexico City. In Mexico 107 species of indigenous and cultivated nopales are threatened by the nopal . moth (Cactoblastis aloe vera), An invasive insect from South America and located in the Caribbean near the southern border of the country.
“This species has a high potential for consuming Mexican nopales, both those we use for commercial and indigenous purposes,” said biologist Juan Enrique Fornoni Agnelli, a researcher at the Institute of Ecology (IE) of the National Autonomous University of Mexico. (UNAM). , who studies in the Plant-Animal Interactions Laboratory, along with his collaborators Carina Puig Barre and Cesar Dominguez Pérez Tejada, how this insect moved from South America to the Caribbean as a result of human-encouraged migration.
Although the nopal moth has not yet been detected in the national territory, Vorononi considered the risk of its entry to be high. “It is one of the 20 species under control at all customs, due to the significant risks it entails to the country’s phytosanitary security,” he said.
During the research, which began 10 years ago, they analyzed how this insect was a biological control model for ruderal nopaleras, that is, a species of cactus (nopales of the genus Opuntia) that was promoted in other parts of the world and became a plague.
“In Australia, farmers wanted to control this pest and looked for a natural enemy and found it in South America, where there are species similar to those in the rest of America. This insect is very effective in controlling Opuntia populations, because it eats the stem from the inside and causes the individual to rot,” he explained. entire, so nopal production drops dramatically.
Effective in pest control at a certain time
The moth was brought in 1924 to Australia from the province of Entre Ríos, Argentina, to infest ruderal nopal populations that hampered livestock activity. The procedure was very successful in eliminating thousands of hectares of this product.
From 1930 to 1940, the insect was brought to South Africa for the same purpose, and from there to the island of New Caledonia, Hawaii, and then was introduced to the Caribbean via the Netherlands Antilles, in 1957.
“Then, the insect began to move across the Caribbean, where the species of prickly pear it attacks is native, which is similar to causing the extinction of endemic species,” the scientist said.
In that region also moved naturally by events such as hurricanes and tropical storms, and reached Florida in 1989, invading the peninsula and the Gulf of Mexico in the area opposite the United States, in whose coast there are many nopales.
Today we have 800 km of border with Tamaulipas in the Gulf of Mexico, which is very close to entering the country. In 2005 it was discovered in Isla Mujeres and Isla Contoy, Quintana Roo, and the Ministry of Agriculture and Rural Development, through the National Health, Safety and Quality Service, controlled this invasion. And in 2009, the country was declared free of this invasive insect, and an intensive monitoring and surveillance program began in the areas most at risk: the northern border, the Gulf and the Yucatan Peninsula.
Fornoni said that 350,000 tons of stalks are produced in Mexico annually, and about 50,000 people work to grow them in different states of the country. “There are many potential impacts, not only on the economy, but also on the social development of many places, as well as impacts on the genetic resources that national lands have as a storehouse and center for biodiversity, where cacti have been domesticated.”
In the Plant-Animal Interactions Laboratory, Fornoni and his team have generated evidence of evolutionary biology through molecular tools to identify sources of infection if this insect enters the country, and the federal government can take action at the border in an effective way in order to control it.