Natural defense

Brazil needs to develop its own biological pest control technology for agriculture that is adapted to the country's agricultural profile, says José Roberto Postalli Parra of Esalq, one of the 56th Bunge Foundation Award winners.

By Elton Alisson

Agência FAPESP – Brazil needs to continue to develop its own biological control technology for agricultural pests in order to minimize economic damage these natural blights cause the country’s farming sector.
The evaluation was made by José Roberto Postali Parra, full professor in the Department of Entomology and Acarology at the Luiz de Queiróz College of Agriculture (Esalq), Universidade de São Paulo (USP) in a lecture he gave during the Scientific Symposium on Animal and Plant Health Defense, an event  sponsored by FAPESP and Bunge on September 12.

The event, held in FAPESP’s auditorium, debated advances made in the area of Animal and Plant Health Defense, which together with Oceanography were topics of the 2011 Bunge Foundation Award. The awards ceremony was held on September 13 at the São Paulo State Capitol Building, Palácio dos Bandeirantes.

The symposium, which took place in the afternoon, featured lectures by winners of the award in the “Youth” and “Life and Work” categories. Parra, who was prizewinner in the “Life and Work” category for his career dedicated to research on biological controls of agricultural pests, gave a talk on the current situation and perspectives of the topic in Brazil.

According to the researcher, the biological control of pests—meaning the use of mass produced insects raised in laboratories to combat plant predators—is a reality in Brazil that took decades of studies to implement and propagate throughout the country and the rest of Latin America. However due to the vast spreads of land, Brazilian agriculture presents challenges to the use of the technique because it makes it difficult to take samples of the natural enemies of a given pest.

Because of this, according to Parra, Brazil can’t use the biological control technologies developed in Europe, for example, where biological control of pests is used in hothouses—structures like greenhouses that provide ideal conditions for cultivation—but should rather seek to develop its own technology, adapted to its extensive agricultural areas.

“It’s necessary to keep developing our own technology for agriculture in Brazil and use Brazilian biodiversity, which is little known and explored for this use,” he said. Integrated pest management was introduced in Brazil in 1970 with soya, where growers began employing biological controls or pheromones for sample studies of pests and natural enemies.

According to Parra, today 3.5 million hectares of sugarcane and 300,000 hectares of soya are controlled biologically in Brazil. It is one of the largest biological pest control programs in the world.

“Nearly half the planted sugarcane area in Brazil is controlled biologically. It’s an impressive number that places Brazil at the forefront in Latin America and on par with the world’s most developed nations in this respect,” he compared.

One of his group’s greatest biological pest control success stories was that of the citrus leaf miner, which appeared in orange plantations in São Paulo State in 1996. Through development of a growing technique for a small wasp (Ageniaspis citricola) brought from Florida in the U.S., which eats the citrus leaf miner’s eggs, researchers managed to invert the increase in numbers of the population of the insect pest.

The project, entitled, “Bioecology and biological control of the citrus leaf miner Phyllocnistis citrella and its relationship with Citric canker”, received FAPESP funding. “The introduction of Cotesia flavipes from Trinidad and Tobago resulted in reduced losses due to damage caused by the sugarcane borer in harvests in the state of São Paulo from US$ 100 million to US$ 20 million,” he said.

Tritrophic systems

In recent years, Parra has been working on development of another species of wasp to combat the “greening” plague, transmitted by an insect called a psyllid that introduces a bacteria to the plant, making it yellow.
The project, called “Bioecology and development of control strategies of Diaphorina citri Kuwayama (Hemiptera: Psyllidae), vector of the greening-causing bacterium”, also received FAPESP funding.

“We can’t think about a very large application of this insect to orange crops because 22 or 23 applications of insecticides are already being made to combat the new disease. And we have a very strong culture of insecticide use in the country. Farmers want to see insects die, not use them to combat plagues,” he said.

Today, Parra is dedicating himself to the study of relationships between natural enemies, parasitoids and plants—the so-called tritrophic interactions—for development of pheromones and other volatiles that attract insects and act in the biological control process, in coordinating the Thematic Project called “Technological bases for the identification, synthesis and use of semiochemicals in agriculture”.

“We have the potential to apply biological pest controls to corn, cotton, eucalyptus, saccharin sorghum, vegetables and soya crops. This technology in Brazil today is much more fact than it is fiction,” he pointed out.