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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.

an increase in leaf coverage for the top leaves with increasing airspeed, and a better coverage in the middle Conventional over-the-row sprayers achieve very little deposit on of the canopy at full airspeed. At 94 L ha Ϫ1 , the top leaves near the ground and on the underside surfaces of leaves throughout the canopy. Air assistance has the potential to improve leaf coverage was not affected by increasing airspeed. deposition of droplets on these leaf surfaces. To gain some insight However, middle leaf coverage of the canopy was the on the effect of air assistance, the effects of airspeed, airflow rate, best at the highest airspeed. and air jet orientation were isolated. The study was carried out in On potatoe (Solanum tuberosum L.), Cooke et al. a spray chamber with a standard spray boom over micro-plots of (1990) obtained a better coverage for the middle and greenhouse grown broccoli (Brassica oleracea var. botrytis L.) plants.lower parts of the canopy with high airspeed (36 m s Ϫ1 ). Air was delivered slightly behind the nozzles from a variable widthThe coverage of the top leaves was the best at a medium slot producing a uniform two-dimensional air jet. The orientation of airspeed (25 m s Ϫ1 ). Jeffrey and Taylor (1991) used a the air jet with respect to the vertical could be adjusted from Ϫ10 to Hardi Twin air-assisted sprayer at three airspeeds (15, 40؇. The ranges of the independent variables were airspeed, 0 to 36 22, and 28 m s Ϫ1 ). On the upper side of leaves, they m s Ϫ1 ; airflow rate, 0 to 1.3 m 3 s Ϫ1 m Ϫ1 , and air jet angle, Ϫ10.2 to 40.2؇. Two sets of flat fan nozzles (Volume Median Diameter ϭ 230found that the coverage in the upper section of the and 400 m, both delivering 250 L ha Ϫ1 at 6 km h Ϫ1 ) were used to canopy was lower with increasing airspeed while at the carry out two full sets of experiments. Results showed that airspeed

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