Abstract. Sweet corn requires many insecticide applications to control its main pest: the European corn borer () (Lepidoptera: Crambidae). The use of is an effective biological alternative to control the European corn borer in sweet corn. However, manual introduction at large scale of using Trichocards is time-consuming. Mechanized introduction of using a boom sprayer is an innovative and advantageous solution. The objective of this study was to design and test a boom sprayer to spray (Hymenoptera: Trichogrammatidae) in sweet corn canopy under real field conditions. parasitized eggs were sprayed at a rate of 800,000 individuals ha-1 using a boom sprayer designed at the Department of Soils and Agri-Food Engineering of Université Laval, Québec, Canada. parasitized eggs were also introduced at a rate of 500,000 individuals ha-1 using Trichocards. Overall, eight releases were made during the 2016 season. Field trial results showed a 17.22% emergence rate reduction of in the sprayed plots compared to Trichocards. Total fecundity and longevity of sprayed females were not negatively affected by spraying; indicating that spraying did not have any negative impact on their quality. The parasitism rates observed on natural egg masses of and on sentinel egg masses of were comparable for both methods. At harvest, sprayed and Trichocards treatments resulted in adequate control of the European corn borer. Obtained results also showed that spraying was 1.7 times faster than the manual introduction of Trichocards. Overall, the results indicate that spraying is a promising technique for an efficient and viable introduction of parasitized eggs. However, more research is recommended to further optimize the spraying parameters. The spraying system successfully used in sweet corn could also be used in corn production and adapted to other crops such as pepper, beans, and potatoes to control the European corn borer. Keywords: Biological control, European corn borer, Ostrinia nubilalis, Trichogramma, Trichogramma ostriniae, Sweet corn, Corn production, Spraying, Boom sprayer, Beneficial insects, Trichocards.

Abstract. The European corn borer, (Hübner), is the major insect pest of sweet corn in the province of Quebec, Canada, and around the world. The presence of this pest results in substantial yield decreases and profit losses for farmers. Currently, chemical insecticides are the main method used to control this insect pest. Nevertheless, there are some interesting alternatives to chemicals for controlling the European corn borer, in particular the use of predator insects. Many research studies demonstrated the effectiveness of using wasps to successfully control the corn borer. However, this biocontrol method is more expensive and complex than chemical insecticides. The main objective of this research study was to investigate the technical feasibility of spraying pupae to facilitate the implementation of this method and reduce operating costs. For this purpose, many experimental trials using were carried out in the laboratory, with the objective of finding a suitable aqueous solution that both disperses the pupae in the sprayer tank and causes them to adhere to corn leaves once sprayed. A laboratory-scale spraying system was also designed and built to check the viability of T pupae after immersion in the spray solution and spraying. The viability of pupae was investigated further using a field prototype boom sprayer. The results showed that it is possible to spray pupae while preserving their physical integrity. In addition, a mixture of guar gum and xanthan gum was found to be the most suitable for the adhesion of pupae to corn leaves. The system overall decreased the emergence rate of Trichogramma by 10% to 15% which is considered acceptable by the authors. The success of this spraying technique for controlling the European corn borer in corn crops is highly valuable and could be generalized to other predator insects. Keywords: Biocontrol, Emergence rate, European corn borer, Spraying system, Sweet corn, Trichogramma ostriniae.