LAB REPORT 8

BIOLOGICAL CONTROL AGENT (BCA)

INTRODUCTION

It is common for fungi, bacteria, viruses, and other microorganisms to infect plants. Due to their special traits, which include high survival rates in adverse environmental conditions, short life cycles, and rapid reproduction rates, fungi rank among the most significant hostile microorganisms. Numerous fungus species with significant potential as BCA have also been found in earlier research; Trichoderma harzianum is one of the key species. Soil has been used to isolate the asexual fungus Trichoderma harzianum.

Biological control is a green method that has a good chance of lowering a farm's inoculum or pathogen levels. This strategy involves the introduction of antagonistic microorganisms that, via a variety of ways, will prevent the growth of diseases. By reducing reliance on chemical pesticides that can endanger the environment, beneficial creatures, and human health, BCA aims to manage these targets in a sustainable and ecologically friendly manner.

OBJECTIVE

To observe the antagonist effect of Trichoderma harzianum against Ganoderma boninense using dual-culture technique.
To calculate the Percentage Inhibition of Radial Growth (PIRG) of Ganoderma boninense.

MATERIAL

Trichoderma harzianum culture

Ganoderma boninense culture

Potato Dextrose Agar (PDA)

Bunsen burner

Scapel

Forceps

70% ethanol

PROCEDURE

The work area and equipment were wiped with 70% ethyl alcohol
Trichoderma harzianum and Ganoderma boninense fungi was prepared and isolated from the pure culture one week earlier during the laboratory session.
An agar was cut in about 5mm from PDA culture plates of Ganoderma boninense isolate and place the disc at the periphery of PDA plate. Allowed the fungus to grow for 4 days at room temperature.
Put an agar disc of T. harzianum 1 cm away from the periphery on the same PDA plate but at the opposing end .
In a control PDA plates, place only G. boninonse disc at the periphery (end) of the PDA plate without the presence of antagonist (T. harzianum).
The inoculated plates were incubated for 2 days at room temperature.
The suppreseeion were observed the the suppression effect of T. harzianum on the G. boninonse isolates in the dual culture plates.

RESULT

Control plate (R1)

Dual plate (R2)

DISCUSSION

The radial growth inhibition (PIRG) percentage score of 38.10% indicates a modest level of efficacy in inhibiting fungal pathogen growth. Trichoderma harzianum have surpessed and dominate the Ganoderma boninense. This suggests that the treatment has a partial inhibitory effect on the target organism's radial growth, but the results are insufficient. Although 38.10% inhibition is always achieved by standard fungicides, it may not be ideal. Antagonism and competition define the relationship between Trichoderma and Ganoderma in biological control. Through processes including mycoparasitism, in which it uses enzymes to attack and break down Ganoderma hyphae and produces antifungal substances that stop Ganoderma from growing, Trichoderma fights Ganoderma. Furthermore, Trichoderma quickly invades the rhizosphere and deprives Ganoderma of the resources it requires for survival by competing with it for nutrients and space. Trichoderma is a very successful biological control agent for treating Ganoderma-related crop diseases because of its combined action, which also makes it a more environmentally friendly option than chemical fungicides.

QUESTIONS

List three other species of fungi that has been identified as potential biological control agents against the plant pathogen.

Piriformospora indica
Myrothecium verrucaria
Metarhizium anisopliae

Briefly explain different modes of action perform by BCA to inhibit or to control the growth of fungal pathogen.

Direct Suppression: BCAs may directly attack or inhibit the target organism.
Environmental Modification: They may alter the environment to make it unfavorable for pests, such as changing soil microbiota to suppress disease-causing fungi.
Induced Resistance: Some BCAs stimulate the host plant's natural defense mechanisms, increasing its resistance to pests or diseases.

CONCLUSIONS

In conclusion, we were able to observe the antagonistic effect of Trichoderma harzianum on Ganoderma boninense using the dual-culture technique and calculate the Percentage of Inhibition of Radial Growth (PIRG) of Ganoderma boninense. The antagonistic interaction between Trichoderma harzianum and Ganoderma boninense was also demonstrated using this dual-culture technique. The outcome was that Trichoderma harzianum eliminated the antagonistic behavior by either directly preventing G. boninense's growth or by engaging in competition for nutrients and space. This indicates that T. harzianum may be used as a biological control agent to prevent plant infections caused by G. boninense. A higher PIRG rating as a result suggests that BCA is more successful. As a result, a substantial percentage of Ganoderma infections are treated with T. harzianum as a biocontrol agent.

REFERENCES

Pandit, M. A., Kumar, J., Gulati, S., Bhandari, N., Mehta, P., Katyal, R., Rawat, C. D., Mishra, V., & Kaur, J. (2022). Major Biological Control Strategies for Plant Pathogens. Pathogens, 11(2), 273. https://doi.org/10.3390/pathogens11020273
Singh, J., & Negi, A. (2022). Role of Biological Control in Plant Disease Management. ResearchGate, 3–19. https://www.researchgate.net/publication/367782906_Role_of_Biological_Control_in_Plant_Disease_Management
Thambugala, K. M., Daranagama, D. A., Phillips, A. J. L., Kannangara, S. D., & Promputtha, I. (2020). Fungi vs. Fungi in Biocontrol: An Overview of Fungal Antagonists Applied Against Fungal Plant Pathogens. Frontiers in Cellular and Infection Microbiology, 10. https://doi.org/10.3389/fcimb.2020.604923

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