AGRICULTURE: Giant Moth Threatens Latam Potato Crop

By IPS Correspondents Reprint | | Print |

Zoraida Portillo

LIMA, May 24 1998 (IPS) - A plague of giant moths, seemingly resistant to most insecticides is threatening potoato crops across most of Latin America.

Originally from Central America, the giant month, also known as “tecia” or the “Guatemalan moth” has been spreading throughout the region and farmers have little option but to learn to live with the voracious bug, says Fernando Ezeta, representative for the International Potato Center (CIP) for Latin America and the Caribbean.

The CIP has been studying the insect, which attacks tubers while leaving the rest of the otato plant intact, since its first appearance in the 1970s.

Costa Rican authorities created the National Potato Commission in 1972 to confront the problem, yet they were unable to impede the propagation of the moth in the major potato-growing regions in spite of the desperate attempts of producers, who utilized ever- larger quantities of insecticides.

In 1983, the moth reached South America through a shipment of potato seeds from Costa Rica to Tachira, Venezuela. From there, the moth spread to Colombia, sweeping through seven of that countrys 32 northern, central and southwestern departments.

The drought which affected Colombia at the beginning of this year with the appearance of the El Nino weather phenomenon, contributed to the plague’s expansion with catastrophic results for small and medium potato growers.

It is calculated that the moth affected 14,000 hectares of farmland, leading to losses estimated at 200,000 metric tons of potatoes.

In Colombia, some 165,000 hectares of potatos are planted each year. These produce some 2.6 million tons of the crop, with an estimate yield rate of 16 tons per hectare. The potato fields are located between 2,100 and 3,500 metres above sea level – which is the most favorable altitude for the reproduction of the giant moth.

In some departments, such as Boyaca, the moth has ravaged crops to the extent that more than 12,000 peasants are having to auction their lands to pay the debts they incurred trying to fight the insect.

During a visit to Lima, Peru, Augusto del Valle, President of the Federation of Colombian Potato Growers, revealed that the giant moth had proven resistant to more than a dozen different insecticides. Worse various pesticides have been used indiscriminately which have killed off natural enemies of th e moth.

Del Valle, along with a groups of Colombian officials and scientists, visited t he Peruvian capital to warn authorities about the risk of the spread of the moth to that country, and to coordinate preventive measures with CIP specialists.

The plague forced Colombia to import 18,000 tons of potatoes for the first time in its history and paralyzed potato exports to neighboring Venezuela as a resu lt of the high costs of fighting the insect. According to Del Valle, the result ing decrease in productivity, moreover, cause the price of the crop to rise, ma king it less competitive on the international market.

Cesar Ocampo, from the Colombian Institute for Agriculture (ICA), stated that the plague became uncontrollable as a result of the El Nino phenomenon, but recognized that the CIP had begun implementing a series of integrated practices to fight the plague.

With the help of this international institutions, which is based in Lima, potato growers in agricultural zones that have been declared emergency areas in Colo mbia have received training in ways to confront the moth, starting with the utilization of healthy seeds.

One of the main components of CIP’s integrated technological plan to confront the plague is the use of traps that utilize a sexual- attraction chemical. Experts consider that 80 adult moths per trap in one week constitutes a high level of infestation but up to 900 adult moths have been found in a trap.

Another strategy to confront the giant moth is the use of baculovirus, a biolog ical insecticide which does not affect the health of humans or animals, and whi ch does not harm the environment, according to the CIP.

Entomologist Maria Palacios says “we advise farmers, for example, to submerge the sacks of potatoes in salt water f or two hours. This kills the moth eggs and causes the larvae to explode.”

The plague has began to affect potato crops in Ecuador as well. Recent studies carried out by specialists in that country have detected high levels of infesta tion in the border province of Carchi. According to newspaper reports the giant moth has been found in Cotopazi, in the central area of the country, which showed the plague was advancing southwards.

Its arrival in Peru would be catastrophic for potato production in the Andean region. It would also have a tremendous impact on Bolivia, since the climates in both of these countries are more arid than those of Ecuador and Colombia, which favors the propagation of the insect, Ezeta explained.

Peruvian authorities have declared a red alert to prevent the entry of the moth into the country. The National Service of Agrarian Health (Senasa) has installed 516 moth traps that utilize sexual pheromones in 8 border areas whic h are considered high-risk zones due to the heavy influx of potatoes from Ecuador. Each trap is capable of detecting the presence of the giant moth in a radius of 10 square kilometers, according to Elsa Carbonell, the head of Senasa. The gre atest worry, however, is the clandestine entry of potatoes into the country.

In order to prevent it, Senasa intends to confiscate all potato shipments that cannot legally demonstrate their place of origin. Those that are certified will also be retained for 40 days to insure their health, and tests will be conducted in stores, distribution centers and other sites of control. (FIN/IPS/zp/mj/dv/mg/98)