Timing of PGPR application

Oct 13, 2025 by wbrum.org 33 views

The Influence of Plant Growth Promoting Rhizobacteria on the Attack of Spodoptera Litura Fabricius (Lepidoptera: Noctuidae) in Soybean Plants

Introduction

Grayak caterpillars (Spodoptera Litura F.) are one of the most significant pests that have a wide range of host plants, making them a major threat to agricultural productivity. On the other hand, Plant Growth Promoting Rhizobacteria (PGPR) has emerged as a promising solution for biological control, which can help reduce the population of this pest by inducing resistance in plants. This study aimed to investigate the effect of PGPR on the attack of grayak caterpillars on soybean plants.

Background

Spodoptera Litura Fabricius is a polyphagous pest that can infest various host plants, including soybeans. The use of chemical pesticides has been the primary method of controlling this pest, but it has several drawbacks, including environmental pollution and the development of pesticide-resistant pests. Therefore, there is a need to explore alternative methods of pest control, such as the use of PGPR.

Methodology

This study was conducted in the Greenhouse of the Faculty of Agriculture, University of North Sumatra, from March 2018 to February 2019. The experimental design used was a factorial random group (rack) with two treatment factors. The first factor was the PGPR dose, which consisted of controls (without PGPR), 50 ml, 100 ml, and 150 ml. The second factor was the time of PGPR application, which was tested at the age of the plant 2 weeks after planting (MST), 4 MST, and 6 MST.

Results

The results of this study showed that the time of PGPR application had a positive effect on the number of soybean pods produced. The average number of pods obtained was 21.25 seeds for treatment of 2 MST, 16.31 seeds for 4 MST, and 14.31 seeds for 6 MST. This indicates that the application of PGPR at an earlier stage of plant growth can lead to better results.

Discussion

PGPR has an important role in increasing plant resilience to pest attacks. The mechanism of action of PGPR in stimulating plant growth and increasing resistance to pests such as Spodoptera Litura includes the production of secondary compounds that can function as inhibiting substances for development and pest activity. In addition, PGPR also triggers biochemical defense mechanisms in plants, so plants are more able to fight pest attacks.

The importance of the PGPR dose in this study cannot be ignored. The right dose can maximize the benefits of PGPR, both for plant growth and in increasing resistance to pests. It appears that with an increase in PGPR doses, it is narrated that plants can issue more optimal responses, resulting in more pods.

On the other hand, the opportunity to conduct PGPR applications also shows useful results. Applications performed at the age of younger plants (2 MST) are proven to give better results compared to applications at an older age. This shows the importance of application time in PGPR-based pest control strategies.

Conclusion

This research provides a clear picture of the potential of PGPR as a biological control agent for pests. The use of PGPR can not only support the growth of soybean plants, but also reduces the risk of pest attacks that can harm the yield. Given the challenges faced in modern agriculture, such as the use of excessive chemical pesticides, biotechnological-based approaches such as the use of PGPR are worth optimizing in sustainable agricultural practices. Through this research, farmers are expected to be able to use PGPR as an environmentally friendly alternative in pest management, as well as to increase their soybean harvest.

Recommendations

Based on the results of this study, the following recommendations are made:

Optimize PGPR dose: The right dose of PGPR can maximize the benefits of PGPR, both for plant growth and in increasing resistance to pests.
Timing of PGPR application: The application of PGPR at an earlier stage of plant growth can lead to better results.
Use of PGPR in sustainable agriculture: PGPR can be used as an environmentally friendly alternative in pest management, and can also increase soybean harvest.

Future Research Directions

Future research should focus on the following areas:

Mechanism of action of PGPR: Further research is needed to understand the mechanism of action of PGPR in stimulating plant growth and increasing resistance to pests.
Effect of PGPR on other pests: The effect of PGPR on other pests should be investigated to determine its potential as a biological control agent.
Commercialization of PGPR: The commercialization of PGPR should be explored to make it available to farmers and to promote its use in sustainable agriculture.
Frequently Asked Questions (FAQs) about Plant Growth Promoting Rhizobacteria (PGPR) and Spodoptera Litura Fabricius

Q: What is Plant Growth Promoting Rhizobacteria (PGPR)?

A: PGPR is a type of bacteria that lives in the soil and has the ability to promote plant growth and increase resistance to pests and diseases.

Q: How does PGPR work?

A: PGPR works by producing secondary compounds that can function as inhibiting substances for development and pest activity. It also triggers biochemical defense mechanisms in plants, making them more able to fight pest attacks.

Q: What is Spodoptera Litura Fabricius?

A: Spodoptera Litura Fabricius is a polyphagous pest that can infest various host plants, including soybeans. It is a major threat to agricultural productivity and can cause significant damage to crops.

Q: How does PGPR affect Spodoptera Litura Fabricius?

A: PGPR can help reduce the population of Spodoptera Litura Fabricius by inducing resistance in plants. This makes it more difficult for the pest to infest and damage crops.

Q: What are the benefits of using PGPR?

A: The benefits of using PGPR include:

Increased plant growth and productivity
Increased resistance to pests and diseases
Reduced use of chemical pesticides
Environmentally friendly alternative to chemical pesticides
Potential to increase crop yields

Q: How can PGPR be used in agriculture?

A: PGPR can be used in agriculture in a variety of ways, including:

Seed treatment: PGPR can be applied to seeds before planting to promote plant growth and increase resistance to pests.
Soil application: PGPR can be applied directly to the soil to promote plant growth and increase resistance to pests.
Foliar application: PGPR can be applied to the leaves of plants to promote plant growth and increase resistance to pests.

Q: What are the potential risks of using PGPR?

A: The potential risks of using PGPR include:

Overuse of PGPR, which can lead to the development of resistant pests
Contamination of soil and water with PGPR
Potential for PGPR to outcompete native microorganisms in the soil

Q: How can PGPR be optimized for use in agriculture?

A: PGPR can be optimized for use in agriculture by:

Conducting further research on the mechanism of action of PGPR
Developing more effective and efficient methods of applying PGPR
Monitoring the effects of PGPR on pest populations and crop yields

Q: What is the future of PGPR in agriculture?

A: The future of PGPR in agriculture is promising, with potential applications in:

Sustainable agriculture: PGPR can be used as an environmentally friendly alternative to chemical pesticides.
Organic farming: PGPR can be used in organic farming systems to promote plant growth and increase resistance to pests.
Precision agriculture: PGPR can be used in precision agriculture to promote plant growth and increase resistance to pests in specific areas of the field.

Q: How can farmers learn more about PGPR?

A: Farmers can learn more about PGPR by:

Consulting with agricultural experts and researchers
Attending workshops and conferences on PGPR
Reading scientific literature on PGPR
Joining online forums and discussion groups on PGPR.