Any process that stops, prevents, or reduces the frequency, rate or extent of oomycete sporangium development, a process that leads to the formation of oomycete sporangium, a single-celled or many-celled structure that germinates directly to form an infection hypha or differentiate, through specialized cleavage vesicles, into between 10 and 30 zoospores, which is laterally flagellated.
negative regulation of oomycete sporangium development