Full protection

Brazilian tomato farming is one of the agricultural activities where the use of phytosanitary products is, in part, excessive, consuming around US$791.00/ha/year. Although this estimate does not differentiate the reality of production for industrial consumption and “in natura”, it certainly reflects, in part, the situation of the practice of chemical control in tutored crops. In this type of production, that condition is practiced sometimes out of necessity, sometimes out of pure desperation. And, in this way, it negatively influenced the physical and economic health of both the tomato grower and the consumer, as well as the environmental quality of the producing region.

The need is due to the frequent occurrence of pests and diseases with high destructive power. And despair, due to the high production cost associated with the uncertainty of effective control. In Rio de Janeiro, according to Emater estimates, tutored production consumes around R$15/ha.

Among the pests,

, the small tomato borer, has been considered limiting for tomato cultivation for 78 years, generating losses ranging from 20 to 100%, determined more by chance than by the influence of efficient control.

Control measures

Despite advances in research, control of the tomato borer remains exclusively chemical and preventive. Spraying begins when the tomato plant is fruiting and, often, during flowering due to the belief that the attack begins at this stage. Maintained on a regime of 3 times/week, on average, which depending on the time of year results in around 30 to 46 sprays/harvest, their executions generally have low technical quality, both in relation to human resources and the equipment used. .

The efficiency presented by insecticides is normally unsatisfactory, as clearly suggested by literature and field practice. Despite the excessive use of these products, it has not been possible to obtain results at levels that guarantee producers and technicians the necessary confidence in this control methodology, although this may vary according to region and seasonality.

The little knowledge about the pest, despite its importance, and the inadequate use of chemical technology with its consequences, can be used to justify this situation. However, changes in this sense require more time than production can expect.

Management alternative

The Department of Entomology and Phytopathology (DEnF), at the Federal Rural University of Rio de Janeiro, has been dedicating itself to research on this pest in order to seek alternatives for immediate use for its control in Paty do Alferes; the main producing municipality in the State of Rio de Janeiro, responsible for around 30% of the tomatoes sold in Ceasa/RJ. Since 1997, this action has been expanded through the participation of DEnF, in the project “Ecological Management of Tomato Pests and Diseases”, led by the then AgrEvo, under consultancy by GRAVENA Ltda. and bringing together several official institutions linked to research, extension and promotion of tomato farming.

One of the results of this project was the establishment of monitoring strategies, which allowed the reduction of the total number of sprays against the region's main pests by up to 60%.

In relation to the small borer, monitoring made it possible to reduce the number of sprays/harvest by 45%. However, both strategies, monitoring and that conventionally practiced by the producer, maintained the same proportion, allowing that, of the total spraying carried out against crop pests, around 70% were exclusively directed at the small borer and without the minimum guarantee of avoid losses of less than 20%.

At the same time, as an alternative to chemical control of the small borer, based on the profile and urgent production needs of the municipality, a method of protecting the fruits was developed, which consists of bagging tomato bunches in a similar way to that carried out for guavas. The bag, made with “Glassine” paper, measuring 18 x 22 cm and “yellow” vinyl wood glue, was applied to the bunches when the first fruit appeared.

The results achieved during three harvests allowed us to conclude that: bagging does not interfere with the formation and development of fruits; is an effective method of controlling the tomato borer, presenting an effectiveness of over 90%, surpassing the use of insecticides applied technically or not

Consequently, the use of bagging allows adding value to the product by increasing the plastic quality of the fruits, by suspending sprays directed at their surface and, although not evaluated due to cost, we also believe that it constitutes a physical barrier to the deposition of other substances normally used in farming.

In this way, bagging, in addition to being able to serve as a basis for the implementation of “regional quality programs”, becomes a powerful “marketing” instrument. The cost of bagging in relation to or use of insecticide depends on the region, the cost of the insecticide, the method used for spraying and the paper acquisition market. In Paty do Alferes, for 1000 plants with 10 bunches, considering only the costs of insecticide and paper and the purchase of this on the retail market, bagging presents a higher cost than insecticide by around 18.34%. However, if the paper is obtained from the wholesale market, the cost of the insecticide can exceed that of bagging by around 28.43%.

Furthermore, the cost/benefit ratio can be increased through its use only in the first four bunches, considered economically the most noble, those most attacked by the pest and responsible for the infestation in the upper bunches. The critical point for its use is the need to handcraft the bag. Although it does not represent problems for small production, this task is difficult for more traditional producers to accept, and there is a need for the industrialization of such material.

Irineu Lobo Rodrigues Filho, Claudio Marchiori and Leonardo V. da Silva

UFRRJ / CPG - Phytotechnics