most oomycetes produce two types of spores. the main dispersing spores are asexual, self-mobile spores called zoospores. these do chemotaxis toward a food source in surface water. a few oomycetes produce asexual spores that are distributed by wind. oomycetes also produce sexual spores, called "oospores". these are translucent, double-walled, spherical structures which can survive harsh conditions.