What is the Difference Between Alternaria Brassicae and Alternaria Brassicicola

The main difference between Alternaria brassicae and Alternaria brassicicola is that Alternaria Brassicae infests many vegetables and roses whereas Alternaria Brassicicola grows on cole crops.

Alternaria Brassicae and Alternaria Brassicicola are two species of the genus Alternaria. They are major plant pathogens and allergens for humans. They grow indoors and cause hay fever or hypersensitivity reactions that sometimes lead to asthma. Moreover, they are also present in the human mycobiome and readily cause opportunistic infections. In general, at least 20% of agricultural spoilage is caused by Alternaria species.

Key Areas Covered

1. What is Alternaria Brassicae
   • Definition, Features, Importance
2. What is Alternaria Brassicicola
   • Definition, Features, Importance
3. Similarities Between Alternaria Brassicae and Alternaria Brassicicola
   • Outline of Common Features
4. Difference Between Alternaria Brassicae and Alternaria Brassicicola
   • Comparison of Key Differences

Key Terms

Alternaria, Alternaria Brassicae, Alternaria Brassicicola

What is Alternaria Brassicae

Alternaria brassicae is a plant pathogen able to infect most Brassica species including important crops like broccoli, cabbage, and oil seed rape. Generally, there are 299 species of the genus Alternaria. It is a natural part of fungal flora that live everywhere. Normally, they are responsible for decay and decomposition. Their airborne spores can be found indoors and outdoors and in soil or water. Their spores are single, club-shaped, and form long chains. In addition to that, they grow in thick colonies that are usually green, black, or gray.

Figure 1: Alternaria brassicicola Conidia

Furthermore, the agriculture loss by Alternaria species is 20%. It can grow up to 80% loss. Alternaria brassicae infects the genus Brassica, a genus of cabbage in the mustard family. Generally, cruciferous vegetables, cabbages, or mustard plants are the informal names of the Brassica genus. Sometimes, the Brassica genus is called the cole crops.

What is Alternaria Brassicicola

Alternaria brassicicola is a necrotrophic plant pathogen, causing black spot disease on a wide range of hosts, particularly in the genus of Brassica. However, the Brassica genus contains the most economically important crops including cabbage, Chinese cabbage, cauliflower, oilseeds, broccoli, and canola.  Alternaria brassicicola also contributes to various respiratory allergic conditions such as asthma and rhinoconjunctivitis.

Figure 2: Symptoms of Cabbage

Moreover, the conidia of the Alternaria brassicicola are abundant in the outdoor environment from the months of May to late October in the northern hemisphere, peaking in June and again in October. The color of conidia is dark brown and they have smooth walls. The size of the conidia is 60 x 14µm. In addition, its shape is cylindrical to oblong. Further, the initial symptoms are small circular, dark spots on the surface of older leaves. As the spots enlarge, concentric rings develop within the lesions, which are often surrounded by a yellow halo, leading to severe defoliation.

Similarities Between Alternaria Brassicae and Alternaria Brassicicola

• Alternaria brassicae and Alternaria brassicicola are two species of the genus Alternaria.
• Both infect the plants in the Brassica genus.
• Moreover, both cause small circular dark spots on the cabbage.
• In addition, they are necrotrophic plant pathogens.
• In addition, both species can serve as allergens for humans.

Difference Between Alternaria Brassicae and Alternaria Brassicicola

Definition

Alternaria brassicae refers to a plant pathogen able to infect most Brassica species including important crops such as broccoli, cabbage, and oil seed rape while Alternaria brassicicola refers to a fungal necrotrophic plant pathogen that causes black spot disease on a wide range of hosts, particularly in the genus of Brassica, including a number of economically important crops such as cabbage, Chinese cabbage, cauliflower, oilseeds, broccoli, and canola.

Significance

Usually, Alternaria Brassicae infests many vegetables and roses whereas Alternaria Brassicicola grows on cole crops.

Conclusion

In brief, Alternaria brassicae and Alternaria brassicicola are two species of necrotrophic plant pathogens. They also serve as allergens to humans, causing asthma. In addition, both species cause Alternaria leaf spots, which are small circular dark spots on the older leaves. Alternaria brassicae infects vegetables and roses while Alternaria brassicicola infects cole crops. Therefore, the main difference between Alternaria brassicae and Alternaria brassicicola is their type of infection.

References:

1. Alternaria brassicae. Alternaria brassicae – an overview | ScienceDirect Topics. (n.d.). Retrieved August 21, 2022.
2. Wikimedia Foundation. (2021, February 25). Alternaria brassicicola. Wikipedia. Retrieved August 21, 2022.

Image Courtesy:

1. “Alternaria brassicicola conidia” By Seemadua – Own Work (CC BY 3.0 au) via Commons Wikimedia
2. “Alternaria brassicae (Berk.) Sacc. Symptoms on cabbage ” By Agronom – Own Work (CC BY SA 3.0) via Commons Wikimedia