Morphologic features of isolates of Lagenidium giganteum mosquito control agent and L. giganteum mold from mammals. Panel A shows henotypic features in culture of the mammalian pathogen (ATCCMYA-4933, type strain) and panel D shows the biological control (ATCC 36492). The development of spherical and ovoid 40- to 170-μm swelling segments (panels B, C, E, F) was the main feature of both mammalian and biocontrol strains. Panel G shows A tubular body developed from an unseen segmented sporangium form a vesicle enclosing numerous zoospores in a mammalian L. giganteum strain. The kidney-shaped zoospores before release (G) and after release (H, arrows) agree with those in the original description of L. giganteum by Couch (10). ATCC, American Type Culture Collection.