Mise au point d'une technique de pulvérisation des pupes de trichogramme pour la lutte biologique contre la pyrale dans la culture du maïs sucré
|Abstract:||The European corn borer, Ostrinia nubilalis (Hübner), is the major insect pest of sweet corn in the world. Its presence results in important yield decreases. Currently, chemical insecticides are mainly used to control this insect pest. Chemical hazards for health as well as the environment are well documented and still relevant. Nevertheless, some potentially viable alternatives exist. For many years, the biological control using trichogramma has been successful in controlling the corn borer without the adverse effects of chemical pesticides. This biological control method is however more expensive and time and energy consuming than chemical insecticides. For this reason, spraying trichogramma pupae is an easier and inexpensive alternative than the common methods used to introduce trichogramma in the fields. Technical feasibility of inundative release by spraying Trichogramma ostriniae has been investigated in the laboratory. The first trials aimed at finding an adequate aqueous solution to both scatter the pupae in the sprayer tank and stick them to corn leaves once sprayed. An aqueous solution of 3 g/L of xanthan gum and 3 g/L of guar gum allowed obtaining a viscous solution which disperses well the pupae in the sprayer tank, sticks them on corn leaves, and offers a good resistance to simulated rain in the laboratory. Thereafter, a spraying system was designed and built to check the viability of trichogramma pupae after being immersed in the spraying solution and sprayed. Results showed that the sprayed pupae emergence rate exceeded 80% and was comparable to that of unsprayed pupae. The spraying system was also tested on corn crops. An excellent adhesion of droplets to corn foliage was observed. However, rain resistance of the spraying solution must be evaluated under real conditions. Pupae survival should also be checked to confirm the effectiveness of this biological control method.|
|Document Type:||Mémoire de maîtrise|
|Open Access Date:||8 February 2021|
|Collection:||Thèses et mémoires|
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