Effects of fungicides propiconazole and Trichoderma spp. on the mortality and the physiological status of larvae and adult worker honey bees (Apis mellifera L.)

Abstract

Exposure to pesticides may affect the survival and normal physiological functions of the honey bee (Apis mellifera L.). The fungicide propiconazole (PRO) and the biofungicide Trichoderma are widely used in agroecosystems, and their effects on the physiology of the honey bee have been largely neglected in risk assessment procedures. We investigated the mortality and variations in physiological biomarkers of honey bee larvae and newly emerged workers exposed to PRO and Trichoderma. Exceeding the field-recommended concentrations of Trichoderma decreased the survival of newly emerged bee workers significantly through oral exposure. PRO, however, showed no significant lethal effects. Contact or oral exposure to field-realistic concentrations of PRO and Trichoderma profoundly altered the activities of detoxification, antioxidative, and digestive enzymes along with energy reserve concentrations of honey bee larvae and adult workers. Integrated biological index (IBRv2) values suggested potential risks of PRO and Trichoderma to honey bees by impairing the physiological status of larvae and newly emerged workers.