This study investigated whether two plant parasites that cause powdery and downy mildew could trigger asthma-like reactions in mice. Researchers found that extracts from these fungi induced immune responses similar to those caused by known allergens like ovalbumin, though somewhat weaker. The results suggest these organisms should be recognized as potential sources of respiratory allergies in humans. This finding may help explain some cases of allergies where the specific cause has been difficult to identify.