Can we limit insect pressure on pasturing cows thanks to trees?

Summary

Insect pressure on grazing animals is increasing with global warming. Using chemical products to protect grazing animals is not permitted on organic farms. Some trees (e.g. walnuts) have a repellent effect on insects and animals could benefit from these trees in agroforestry systems. In our trial, we assessed insect pressure on 6 herds of cows on pasture with/without trees. We evaluated insect pressure per herd with one H-traps in the meadow and sticky traps in various tree type, observed defensive behaviours of cows and counted flies on the animals.