Decode the packet. Choose with confidence.
Plant Disease Resistance Codes
Look up the abbreviations used on Urban Farmer seed listings, learn what each disease is, and understand what resistance can—and cannot—do.
A resistant variety may slow disease development or reduce damage, but it can still become infected.
Some abbreviations are reused. Always read the full disease name shown for the specific crop or variety.
Rotation, sanitation, airflow, healthy soil, and accurate diagnosis remain important.
Urban Farmer disease glossary
Find a resistance code
Search by abbreviation, disease name, symptom, or pathogen type.
How to read a listing
Codes describe a breeding claim
- Codes identify the disease or pest for which a variety has documented resistance or tolerance.
- Resistance can be race- or strain-specific; numbers after a code may identify the tested races.
- HR usually means high resistance. IR usually means intermediate resistance.
- A code without a race number should not be assumed to cover every known race.
Important diagnostic note
Symptoms can look alike
Wilt, yellowing, leaf spots, and root decline may have disease, insect, environmental, or nutritional causes. Use this glossary to interpret product codes—not to make a final field diagnosis.
Research and terminology sources
Urban Farmer's sheet supplies the code/name pairs. Disease explanations were checked against plant-pathology and Extension references.