Resistance to anthelmintic drugs is a threat to equine welfare. Like antibiotics, is restrictive use of anthelmintics necessary to retain their effectivity. Thus, targeted selective treatment, based on individual deworming, was introduced a decade ago. However, we have shown that the prevalence of, Strongylus vulgaris, the most pathogenic and feared parasite of horses, has increased since then. Deworming all horses on a regular basis is not a solution of this problem. We need to develop alternative methods to drugs for parasite control. The aims of this project are to a) investigate the survival of overwintered S. vulgaris larvae on pasture b) investigate a predatory fungus which trap parasitic larvae on pasture c) develop clinical diagnostic markers for migrating S. vulgaris larvae. It is vital to reduce the use of anthelmintic drugs without an increased risk of parasitic diseases. The results from this project will introduce new approaches to control and diagnose strongyle parasites.