Biological control programs by the International Institute of Tropical Agriculture (IITA) and partners on cassava green might have brought benefits worth more than $1.7 billion to Nigeria, Benin, and Ghana in 18 years.

Dr Ousmane Coulibaly, IITA Agricultural Economist, who disclosed this in a statement, made available to the press during the week described the figure as ‘a conservative estimate.”

“The figure represents the amount those countries would have spent over the years on other methods such as chemical control and or yield losses if they never adopted biological control,” Coulibaly said at a seminar in Ibadan.

Rice Farm

He identified the cassava green mite as a pest that was responsible for between 30 per cent and 50 percent yield loss of cassava in Africa, until a natural enemy of the pest helped contain the devastation.

Coulibaly recalled that in 1993, scientists from IITA and partners identified, Typhlodromalus aripo, as one of the most efficient enemies against cassava green mite.

He said the introduction of T.aripo, another chemical, had reduced pest populations by as much as 90 percent in the dry season, when pest populations were usually high.

He said in the wet season, pest attacks were, however, not as severe, adding that T.aripo was first released on cassava farms in Benin after it had been transported from Brazil and, subsequently, in 11 countries.

The Agricultural Economist pointed out that T.aripo had been established in all of the countries mentioned, except Zambia.

“T. aripo has also spread into Togo and Côte d’Ivoire from neighboring countries. It spread at about 12 km in the first year, and as much as 200 km in the second year.

“Today, the cassava green mite predator has been established on more than 400,000 square kilometers of Africa’s cassava growing areas,” he said.

The release of T. aripo, he added, benefited Nigeria by about S1.367 billion, followed by Ghana, $305 million, and Benin $54 million respectively.

The statement quoted scientists as saying that the control of the pest, through the application of toxic chemicals, was ruled out because of their possible adverse effects on illiterate farmers and the environment.

They said that disease pathogens and pests tended to gradually develop resistance to chemical pesticides over time.

According to them, most chemical pesticides are not selective and may destroy the natural enemies and the pests together.