Many types of diseases can carry over to the next season in your soil and sometimes even on your saved seed. You may want to consider growing some resistant varieties or using them as rootstock for your favorite heirlooms that need just a little bit of help defending themselves in the throes of the growing season. In some cases, there are multiple codes listed for different strains of the same disease. As well, seed companies in different regions of the world may present the same disease code in different ways, which can be a bit confusing. For continuity, the tomato disease codes listed below are codes that are typically found in official tomato registers in several countries across the globe.



1. BS or (Pst/Pst: 0) – Bacterial Speck (Races 0) Scientific Name: Pseudomonas syringae

2. BW – Bacterial Wilt Scientific Name: Erwinia tracheiphila



1. A – Anthracnose Scientific Name: Colletotrichum lagenarium

2. A / Aal / AS/ ASC – Alternaria Stem Canker Scientific Name: Alternaria alternata f.sp. lycopersici

3. BS – Black Speck Scientific Name: Rhizoctonia ssp



1. T or TMV – Tobacco Mosaic Virus Scientific Name: Tobacco mosaic virus, positive-sense single-stranded RNA virus (Tobamovirus)

2. ToANV – Tomato Apex Necrosis Virus Scientific Name: Tomato Apex Necrosis Virus

3. ToMV or (ToMV:0-2) – Tomato Mosaic Virus (Races 0, 1, and 2) Scientific Name: Tobamovirus



1. N or (Ma/Mi/Mj) – Root-Knot Nematode Scientific Name: Meloidogyne spp., Meloidogyne arenaria, M. incognita, M. javanica

Two additional codes that are sometimes found on seed packages characterize the level of resistance of a particular variety to a given disease:

1. HR= High Resistance
2. IR= Intermediate Resistance