This article was written by Jorge Luis Alonso G., an information consultant specializing
in the potato crop.
Researchers at Bangabandhu Sheikh Mujibur Rahman Agricultural University, Hajee Mohammad Danesh Science and Technology University, and the Asian Institute of Technology conducted a study to evaluate the biological control efficacy of Trichoderma harzianum in combination with organic amendments against potato stem rot caused by Sclerotium rolfsii.
This article is a summary of a scientific paper about the study that was published in the journal Plant Stress in June, 2023.
Potato is the world’s fourth most important carbohydrate crop, and Bangladesh is the seventh largest producer. But there’s a looming challenge. The bountiful crop is threatened by destructive fungal and bacterial diseases, such as the infamous stem rot caused by Sclerotium rolfsii. These rampant diseases wreak havoc on production and storage, creating an urgent problem.
To make matters worse, climate change is entering the equation and contributing to significant losses in potato yields. While traditional measures such as chemical control with fungicides have often been used to combat the threat of stem rot, their effectiveness is declining. The culprit? Rapid resistance development.
The potential of an innovative alternative
However, an innovative alternative is emerging. The fungus Trichoderma harzianum could be a game changer, given its proven ability to inhibit the growth of harmful fungi.
But how can its effectiveness be maximized? The answer may lie in microencapsulating T. harzianum spores and using them in conjunction with organic additives. These additives aren’t just benign; they actually improve soil health and create a more supportive environment for fungi.
With all these facts in mind, current research is gearing up to dive deeper into this potential solution. The focus is clear: explore the biological control approach to potato stem rot caused by S. rolfsii.
The researchers began their investigation with an in vitro dual culture assay. The results were precise: the antagonistic activity of T. harzianum against S. rolfsii was undeniable, inhibiting its growth by an impressive 63%.
This test was based on previous studies. These studies had shown that T. harzianum has the ability to produce enzymes that can suppress the growth of S. rolfsii and even cause cell destruction.
However, the researchers knew they needed to go further to gain a more holistic understanding of its efficacy. So a polyhouse trial was set up, marking a significant advance in their research journey.
The promise of a fungus
T. harzianum has made a name for itself in the world of plant science. It is well known for its ability to suppress a wide range of plant pathogens. Remarkably, when T. harzianum was combined with organic amendments — substances celebrated for their ability to improve soil health and promote microbial establishment — its effectiveness in reducing disease severity increased significantly.
In fact, there was an astounding 42.8% increase in efficacy. This resulted in a corresponding rise in the yield of healthy tubers and an encouraging reduction in unhealthy tubers.
In addition, it was observed that the strategic application of T. harzianum and organic amendments could arm potato plants with an improved defense response against the infamous stem rot disease caused by S. rolfsii.
Digging deeper into the specifics of the treatments, the study found that the combination of T. harzianum and tea waste stood out from the rest. This particular treatment proved to be particularly effective in restoring the health of diseased potato plants. The secret weapon? Probably the bioactive compounds found in abundance in tea waste.
Overall, the research came to an optimistic conclusion: organic amendments could be a game changer. Their use could significantly increase the efficacy of T. harzianum against S. rolfsii, making monumental strides in improving soil health and promoting vigorous plant growth.
Source: Chowdhury, M. R., Ahmed, S. F., Khalid, B., Bony, Z. F., Asha, J. F., & Bhuiyan, M. K. A. (2023). Biocontrol efficiency of microencapsulated Trichoderma harzianum coupled with organic additives against potato stem rot caused by Sclerotium rolfsii. Plant Stress, 9, 100181. https://doi.org/10.1016/j.stress.2023.100181
Image: The white, radiating mycelium of S. rolfsii visible on potato tubers. Credit University of California Statewide IPM Program (UC IPM)