As agriculture moves towards more sustainable and eco-friendly solutions, biological pest control is becoming central to modern Integrated Pest Management (IPM) systems. Among the many biological agents used, Beauveria bassiana has gained popularity for its effectiveness against a wide range of insect pests. However, for growers seeking maximum control and efficiency, combining Beauveria with other biocontrol agents can be both a smart strategy and a risky move—if not done correctly.

In this blog, we explore the dos and don’ts of mixing Beauveria bassiana with other beneficial microbes and biopesticides.

Why Combine Biocontrol Agents?

Using a combination of biocontrol agents can offer several advantages:

• Broader pest control spectrum

• Synergistic effects that enhance overall efficacy

• Reduced risk of resistance development

• Better resilience in diverse environments

However, not all organisms are compatible. The success of a mixture depends on biology, formulation type, and application method.

Understanding Beauveria bassiana

Before mixing, it’s essential to understand how Beauveria bassiana works. It’s a fungal entomopathogen that kills insects by penetrating their cuticle and growing inside their bodies. It thrives in humid conditions and prefers temperatures between 20°C to 30°C.

Being a living organism, its compatibility with other agents—fungi, bacteria, or botanicals—depends on factors like:

• pH of the solution

• Moisture content

• Shelf life and formulation

• UV sensitivity

✅ The Dos: What You Can Mix with Beauveria bassiana

1. Neem-Based Botanical Extracts

Neem oil and Azadirachtin are highly compatible with Beauveria. While neem acts as an insect repellent, Beauveria infects and kills the pests. This combination offers both immediate and long-term control.

Tips:

• Use a mild concentration of neem

• Do not use oil-based carriers that can block fungal spores

2. Pseudomonas fluorescens (Bacterial Bioagent)

This beneficial bacteria is used to combat soil-borne diseases. When used with Beauveria, it protects roots while Beauveria controls foliar pests.

Tips:

• Apply Pseudomonas as a soil drench and Beauveria as a foliar spray

• Avoid mixing in the same tank; use staggered applications

3. Trichoderma viride or Trichoderma harzianum

Trichoderma is a soil-friendly fungus known for fighting root diseases. While Beauveria works above ground, Trichoderma dominates below.

Tips:

• Apply separately: Trichoderma to soil, Beauveria to foliage

• Do not combine in a single spray mix

4. Metarhizium anisopliae

Metarhizium is another entomopathogenic fungus that complements Beauveria. Both can be used together for enhanced pest spectrum coverage, especially against termites, beetles, and aphids.

Tips:

• Use compatible formulations (e.g., wettable powder or suspension concentrate)

• Ensure both strains have similar pH and storage needs

5. Verticillium lecanii

This fungus controls whiteflies and aphids and is known to work synergistically with Beauveria.

Tips:

• Use compatible wettable formulations

• Avoid using with fungicides during application

❌ The Don’ts: What Not to Mix with Beauveria bassiana

1. Chemical Fungicides

This is a major mistake. Most chemical fungicides—especially broad-spectrum types like Mancozeb, Carbendazim, or Copper Oxychloride—kill Beauveria spores, rendering your biocontrol strategy ineffective.

Avoid:

• Mixing fungicides with Beauveria

• Spraying fungicides within 5–7 days of applying Beauveria

2. Strong Surfactants or Spreaders

While surfactants improve coverage, strong chemical-based spreaders can damage Beauveria spores and reduce viability.

Alternative:

• Use biodegradable wetting agents or mild organic emulsifiers

3. Highly Alkaline or Acidic Solutions

Beauveria thrives in a pH range of 6.0 to 7.5. Extreme pH levels reduce its spore viability.

Avoid:

• Mixing with strongly alkaline or acidic products

• Always check product pH compatibility

4. Copper-Based Micronutrients or Pesticides

Copper is toxic to most fungal spores, including Beauveria. Products like Bordeaux mixture or copper oxychloride can kill beneficial fungal agents.

Solution:

• Apply copper products at least one week before or after Beauveria application

Mixing Guidelines and Best Practices

If you plan to mix Beauveria bassiana with other agents, follow these tips:

1. Read Product Labels Carefully
   Always check the compatibility instructions on both products.

2. Conduct a Jar Test
   Mix a small amount of both agents in water and observe for any clumping, foaming, or residue.

3. Use Fresh Water and Clean Equipment
   Contaminated tanks can disrupt fungal spore performance.

4. Apply Immediately After Mixing
   Prolonged holding of mixes reduces effectiveness.

5. Store Separately
   Each biocontrol agent should be stored in its recommended environment to maintain shelf life.

When to Use Combined Biocontrols

• During early infestation for preventive control

• In crops where multiple pest types co-exist (e.g., aphids + thrips)

• In organic farms with strict no-chemical policies

• In IPM setups aiming to minimize synthetic pesticide use

Final Thoughts

Combining Beauveria bassiana with other biocontrol agents is a promising approach for sustainable pest control. However, it must be done with proper understanding and care. Knowing what works together and what doesn’t can make a big difference in pest suppression, crop yield, and long-term soil health.

If you are unsure about mixing partners or application methods, consult your Beauveria bassiana supplier or agricultural expert for tailored guidance. With the right combinations, you can build a pest management program that is not only effective but also environmentally sound.