RESUMO
Harpin(Ea), an active component in Messenger, was originally isolated from the bacterial plant pathogen Erwinia amylovora based on its ability to elicit a hypersensitive response (HR). This bacterial pathogen causes "fire blight", a disease in apples and other members of the Rosaceae. Harpin(Ea) also induces resistance in a variety of plants against a wide array of pathogens. The objective of this investigation was to determine indications of resistance induction to Botrytis cinerea in the plants treated with the formulated Harpin(Ea) protein. This pathogenic agent is responsible for important economic losses in the cultivation of both greenhouse and field grown tomatoes. Plants with and without Messenger applications were inoculated with Botrytis cinerea in the same way. In addition, some plants with and without Messenger applications were not inoculated. Inoculated plants were symptomatologically checked for local and systemic symptoms. Evaluations of the number of tomatoes produced and their growth were also carried out. The results obtained demonstrate that there were active defence systems in the plant, producing a reduction in the damage caused by the pathogenic agent Botrytis cinerea. A greater growth also took place in the fruit obtained. These results show that the formulated Harpin(Ea) protein could reduce the use of chemical agents and be a new tool to serve as the basis for an Integrated Pest Management system.