|Solanum tuberosum (potato)|
This disaster highlighted the danger of using only a very small number of different crop varieties (monoculture). Blight never devastated South America where hundreds of potato varieties are grown, with each variety being both resistant to (and sensitive to) different strains of pathogens.
Reliance on single strains of crops is a danger in modern times also. Educated uses of genes from wild strains is essential for ensuring food security. For example, research funded by the Gates Foundation is looking to utilize genes from wild wheat to combat rust, a fungal disease that's devastating cultivated wheat crops in Africa.