[1] Most species in this group produce a downy mildew disease, which can cause severe damage to many different cultivated crops, as well as wild and ornamental plants.

[5] Peronospora tabacina causes blue mold on tobacco plants and can severely reduce yields of this economically important crop to the point where it has been classified as a bioweapon.

[5][3] Peronospora was first described in 1837 by August Carl Joseph Corda, a Czech mycologist and physician, in his first of six volumes of his Icones fungorum hucusque cognitorum.

[5] Another epidemic that was caused by Peronospora destructor reduced the yield of sweet onions by 25 percent in Georgia, USA in 2012, and led to an estimated $18.2 million in losses.

[5] During sexual reproduction, the hyphae will undergo meiosis forming antheridia and oogonia, the only haploid structures in the Peronospora life history.

[3] Peronspora somniferi was considered for its ability to devastate fields of the opium poppy, which could have targeted areas that depend on the crop.

[3] The United States has classified Peronospora tabacina as a possible bioweapon, because if it were used to target the US tobacco industry, it would lead to major economic loss.

[9] The mitochondrial genome only differed by seven single nucleotide polymorphisms, three small indels, and one copy number variant.