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Agricultural Engineering

Death by dehydration

Soybean oil and saccharose-based biopesticide eliminate agricultural pests

A biopesticide that can control several agricultural pests without damaging the environment and with several advantages over conventional agrotoxins has been developed by the Paulista State University (Unesp). Laboratory and field results have shown the efficiency of the product and aroused the interest of  Technes Agrícola, a São Paulo-based company that has already signed a contract for the exchange of technology  with the university. The product should be available for Brazilian farmers in approximately three years.

“The biopesticide is made from renewable sources, is not toxic to mammals and therefore offers no health risks for those who handle the product or consume food that has been protected by it. It is also biodegradable, does not pollute the environment and does not interfere with the plant’s development,”  explains chemist Maurício Boscolo, a professor from the Biosciences, Arts and Exact Sciences Institute (Ibilce) of  Unesp in São José do Rio Preto, in São Paulo’s inner state area, who coordinated the study on the pesticide.

The product is a compound from the saccharose group. These are substances resulting from the reaction of an acid, in this case the fatty acids of soybean oil, and sugar. The process uses saccharose from sugar-cane and the compounds formed thus are called sucrosteres. According to Boscolo, all the tests so far have shown that despite being produced using common reagents of vegetable origin, the biopesticide is efficient, has great economic potential and generates no waste in the industrial process.

In the contract signed between Unesp and Technes, in addition to the exchange of technology  the company has been guaranteed technical cooperation in the production of the pesticide on a large scale; the company  specializes in the development of organic and mineral fertilizers, supplements and other farming products. The agreement provides for an undisclosed percentage on the sale of the products and the construction, by the company, of a new laboratory at Ibilce, in addition to the refurbishment, estimated  cost R$155,000, of the Applied Ecology Laboratory at the School of Agrarian and Veterinarian Sciences (FCAV), at the Jaboticabal campus, which also houses researchers  involved in the pesticide’s development.

“The product is very good and we’d like to put it on the market quickly. However, we reckon that it’ll only start being sold in three years time. That’s the average time it takes to register a new pesticide with the Ministries of  Health, Agriculture and the Environment,”  says Edson Tsuzuki, a Technes Agrícola partner. The product’s end price and its trade name are yet to be defined, but Tsuzuki guarantees that it will be competitively priced. The company estimates that initial production will amount to 5,000-10,000 liters a month.

Protection from fat
The main feature of the pesticide is that it is a detergent, or tensoactive, a substance capable of reducing surface tension when dissolved in water. It acts directly on the protective cuticle of the bodies of certain pests, such as mites and some insects that have an external skeleton (exoskeleton) with a fine layer of fat, a natural protection whose main function is to prevent water loss. The studies carried out by Boscolo’s group, which also included agronomic engineer Odair Aparecido Fernandes, a professor from FCAV, and biologist Reinaldo Feres, a professor from Ibilce, showed that the pests studied lost weight after being sprayed with sucrosteres. Examination under the microscope showed that this happens because the exoskeleton is affected and as a consequence, there is water loss. “They die from dehydration,”  says Boscolo. “Our biopesticide works in the same way as detergents used to wash dishes. While the latter dissolve the grease on dishes, our product dissolves the fat on pests, in addition to having an adhesive effect that immobilizes some insects and arachnids, such as mites.”

Another important feature of the substance is its selective action,  it preferentially attacks organisms that are harmful to plantations. “It can be used in fruit growing, for example, without killing bees where a product is being used to control pests,”  states Boscolo. It is not yet possible to say on which groups of insects or arachnids the biopesticide will be efficient. “We haven’t conducted trials with ants, for example. With regard to mites we know that the product acts more efficiently upon those classified as phytophagous, which feed on plants, rather than on predatory mites that attack insects and that have a tougher exoskeleton.”

According to the researcher there is no other product manufactured in Brazil with the same characteristics as their pesticide. “As far as we know there is a similar product being made in the USA, but it uses toxic solvents in its manufacturing process, generating waste,”  points out Boscolo.

As occurs with many innovations, the discovery of the pesticide happened almost by chance. “The initial objective of the project, which started five years ago, was different. I’d been given a grant by FAPESP’s Young Researchers program and was studying the development of products derived from saccharose in a sub-area of chemistry called sucrochemistry,”  he says. At first, the intention was to produce non-ionic biodegradable detergents; those used in the kitchen and produced from petrochemical substances are ionic. The researchers also wanted to develop polymers and other derivatives. “As we knew that some sucrosteres found in vegetables were biologically active, we thought about testing the products that we were developing as biological controllers,”  says Boscolo.

The first tests for biological activity were carried out with the whitefly (Bemisia tabaci), considered one of the main pests in the 20th century and responsible for tens of millions of dollars of damage in Brazil. It is highly destructive and capable of adapting to more than 700 types of crop, such as ornamental plants, soy, cotton, beans, melons, tomatoes, sweet potatoes, etc. Laboratory tests and trials on protected crops, coordinated by agronomist Odair Aparecido Fernandes, showed  very efficient control. “Between 90% and 100% of the insect population – which despite its name is from the cricket family – was eliminated. In some cases the pest’s death happened within two hours of applying the biopesticide,”  says Fernandes. Subsequently, equally successful tests were carried out by biologist Feres on a pest that gets into several crops: mites such as Calacarus heveae, Tetranychus urticae and Tetranychus ogmophallos, which attack rubber plants, ornamental plants and peanut fields, respectively.

Improved control
One of the first companies to benefit from the new biopesticide was Athena Mudas, from São José do Rio Preto, which has revenues of  US$6 million a year from exporting ornamental plants to over ten countries in North America and Europe. Throughout 2006, while the substance was still being developed, the biopesticide was tested, on its own or together with other conventional pesticides, and showed it was able to control several pests, especially the whitefly and the striped mite (Tetranychus urticae). “When we used the product on its own, we saw that its effects were felt over the long term and when we used it with other pesticides we saw that it improved  the impact,”  states agronomist José Carlos Salvador Sobrinho, Athena’s technical department coordinator. By using the substance Athena hopes to cut its losses from pest-infected cuttings by nearly US$100,000 a year.

Athena is using the biopesticides on an experimental basis. Unesp signed a contract for six months in July 2006, renewed for a further year in January 2007. Under the terms of the contract the university supplies the biopesticide and Athena pays the production costs and gives two grants to researchers on the project, one a Masters student and one starting in the scientific area. Application of the product is monitored and serves to evaluate the project’s efficiency. The results will also serve to obtain approval of the biopesticide from the agencies in charge of authorizing the use of this type of product.

The Project
Development of saccharose products. Synthesis and study of their physical and chemical properties
Youth Support Program
Researchers from Emerging Centers
Maurício Boscolo – Unesp
R$149,238.99 and
US$89,374.06 (FAPESP)