Sexual Stage: This stage follows a similar pattern to the asexual stage, but with a few exceptions. It is hypothesized that two zoospores fuse together to form a dikaryotic zoospore (with two separate haploid nuclei, n+n) and then infect the roots. Once the infection occurs, the dikaryotic zoospore develops into a binucleate plasmodium (one pair on nuclei, n+n). Similar to the asexual stage, this plasmodium will also replicate its nucleus to create a multinucleate plasmodium (many pairs of nuclei, n+n). The second main different between stages occurs here. The pairs of nuclei (n+n) will fuse by karyogamy, and the plasmodium will quickly divide into numerous resting spores within a sporosori (spore sack, alternatively called cystosori). These resting spores have three-layered walls and are extremely resistant to the environment, allowing them to persist in the soil for longer than 10 years.