Stem infection of Tulsi (Ocimum tenuiflorum) grown in a pot by Botryosporium longibrachiatum

Tulsi is cultivated for religious and traditional medicine purposes by every household in India. It has a place within the Hindu traditions, in which devotees perform worship involving holy basil plants or leaves.

I also have tulsi plants are grown in my balcony, last Sunday morning, I observed white cottony hoar-frost fungal growth on the stem of Tulsi plant (Fig. 1).

Fig. 1 Hoar-frost fungal infestation on Tulsi stem.

To take a close look, I observed a Macro lens with my Samsung S9 phone, I could see elongated and upright conidiophore (Fig. 2).

Fig. 2 Upright Conidiophores of B. longibrachiatum on the tulsi stem.

I took a glass slide, which I always keep at home along with foldscope kit, and transferred the fungal growth from the stem to slide using a needle. After observing it under foldscope, I could see lateral fertile branches in acropetal order (Fig. 3).

Fig. 3 Lateral fertile branches of B. longibrachiatum in acropetal order

After using the digital zoom function of my smartphone, I could capture the conidia, which were hyaline and oval in shape, and often found in clusters (Fig. 4).

Fig. 4 Cluster of conidia of B. longibrachiatum

2 Comments Add yours

  1. Manu Prakash says:

    Dear Praveen,

    What incredible observation and images. The fractal tree like structures are so beautiful.

    Indeed, knowing the identity of this fungus – specially since it’s found on Tulsi – a plant of immense importance in India culture. It would be worth knowing how common is it, what are the consequences and how easily is this infection acquired. Imagine 100’s of millions of tulsi plants in households across India – even if 0.001% people reported if the see an infection like this – it would make for a tremendous data.

    Cheers
    Manu

    1. praveen_rahi says:

      Yes, tulsi is one of the most commonly grown plant, and it is also cultivated in mass-scale for its medicinal properties. There are few reports on Black Stem Caused by Botryosporium longibrachiatum on Sweet Basil and Statice in Korea (https://www.ncbi.nlm.nih.gov/pubmed/30703963; https://www.ncbi.nlm.nih.gov/pubmed/30722371). Botryosporium longibrachiatum (Oudem.) Maire) has been recorded on dead plants of Arachis hypogea, Madras (Subramanian and Ramakrishnan, List of Indian Fungi, J. Madras Univ., B.24:336, 1956). There is a recent report on this species by Rajnish 30114 (PAN), on fallen leaves, Jolplakhin (Bilaspur H. P.), 670m, Oct. 1, 2011. All the studies from India are just based on classical methods, there is a need to validate the identity of this fungus by using molecular markers and test its pathogenicity.

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