Lecanicillium longisporum: A Targeted Mycoinsecticide for Sustainable Pest Management

Overview of the Microbe#

Lecanicillium longisporum, formerly classified under Verticillium lecanii, is a globally distributed, filamentous entomopathogenic fungus in the order Hypocreales and family Cordycipitaceae [1]. It is recognized for its biocontrol potential against a variety of soft-bodied arthropods, including aphids, whiteflies, and thrips [2]. This fungus infects hosts by means of sticky conidia that adhere to the insect cuticle, followed by enzymatic penetration, internal proliferation within the hemocoel, and ultimately host death [3]. Naturally occurring in soil and on plant surfaces, L. longisporum is characterized by long conidia, rapid sporulation, and high virulence under moderate humidity and temperature. These traits make it effective in greenhouse and controlled-environment agriculture.

Entomopathogenic Biocontrol of Aphids#

Aphids such as Aphis gossypii, Myzus persicae, and Macrosiphum euphorbiae are economically damaging pests. L. longisporum has proven highly effective in controlling these pests through conidial adhesion, enzymatic degradation (via proteases, chitinases, and lipases), cuticle penetration, and hemocoel colonization [2]. Infected aphids die within days and serve as platforms for further conidial dissemination.This self-sustaining biocontrol cycle is particularly beneficial for organic and integrated pest management (IPM) systems. Studies have reported mortality rates of up to 85% under favorable humidity conditions, affirming the fungus’s potential [4].

Commercial Formulations and Application#

Several commercial formulations of L. longisporum are in use globally:

•   Mycotal® – one of the first Lecanicillium-based products, developed by Koppert Biological Systems.
•     Vertalec® – derived from strain IMI 179172, formulated for aphid and whitefly control.

These products come in wettable powder and oil-based emulsions suitable for foliar spray or soil drench. They are most effective at 60–80% humidity and 20–28°C [5]. Greenhouse trials have shown significant pest reduction, with Vertalec® achieving a median lethal time (LT₅₀) of 6.9 days in cotton aphids.

Formulation innovation continues, including nano-carriers and UV-protective materials to increase shelf life and efficacy in variable field conditions.

Endophytic and Plant Growth–Promoting Effects#

L. longisporum has demonstrated endophytic capabilities, colonizing internal plant tissues without causing disease [3]. As an endophyte, it stimulates phytohormone production, enhances nutrient uptake, and improves resistance to abiotic and biotic stresses.Dara [6] demonstrated that Lecanicillium spp. increased root and shoot biomass, chlorophyll content, and systemic resistance in crops such as tomato and chili. Moreover, endophytic colonization reduced feeding and fecundity of Aphis gossypii, indicating a secondary defense mechanism [7].

Compatibility with Natural Enemies in IPM#

A core principle of IPM is conserving beneficial insects. L. longisporum exhibits selective pathogenicity toward soft-bodied pests while sparing beneficial insects like:

•     Coccinellid beetles
•     Aphidius colemani (parasitic wasps)
•     Chrysoperla carnea (lacewings)

Zimmermann [8] confirmed its low risk to non-target organisms. Though direct exposure to spores may cause transient effects, populations of beneficial insects typically recover, especially in controlled environments.Thus, L. longisporum fits well into IPM frameworks for sustainable and ecologically friendly pest control.

Challenges and Future Potential#

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Challenges#

•  Environmental sensitivity: UV light, fluctuating humidity, and temperature extremes reduce field performance.
•       Cost and scale: Production and formulation costs remain higher than chemical alternatives.
•       Regulatory barriers: Biopesticide approvals are often complex and slow.
•       Strain specificity: Efficacy can vary based on environment and pest strain.

Future Directions#

•    Developing UV- and desiccation-resistant strains
•   Nano-formulations to enhance shelf life and adherence
•   Genetic enhancement for virulence and stress tolerance
•   Combining with other bioagents and fertilizers
•   Use in vertical farming and hydroponics

Spotlight on Research: Pathogenicity against Sipha maydis and Metopolophium dirhodum#

Brief Overview#

Fadayivata et al. [4] evaluated L. longisporum strain LRC 190 against two cereal aphids, S. maydis and M. dirhodum, under laboratory conditions.

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Key Insights#

•        Dose-dependent mortality observed
•       LC₅₀: 5.9 × 10⁵ conidia/ml for S. maydis, 3.2 × 10⁶ for M. dirhodum
•       LT₅₀ at 1 × 10⁸ conidia/ml: 2.9 days (S. maydis), 4.4 days (M. dirhodum)
•       Reproductive capacity of surviving aphids was significantly reduced

Why This Matters#

These findings validate the use of L. longisporum in cereal pest management. Since S. maydis and M. dirhodum are vectors of barley and wheat viruses, fungal application provides dual control of pests and diseases.

Summary Table: Spotlight Study#

Category	Details
Lead Researchers	Fadayivata, Moravvej, & Karimi
Affiliations	Ferdowsi University of Mashhad, Iran
Research Focus	Pathogenicity of strain LRC 190 on cereal aphids
Key Breakthroughs	LC₅₀ and LT₅₀ data confirm high virulence
Collaborative Efforts	National collaboration, potential field expansion
Publication Date	Journal of Plant Protection Research, 2014
Key Findings	High mortality, reduced reproduction, promising for cereal pest contro

Conclusion#

Lecanicillium longisporum is a promising biocontrol agent offering dual benefits: insect pathogenicity and plant growth promotion. It aligns with IPM goals by targeting specific pests while preserving ecological balance. While there are challenges in field persistence, cost, and regulatory frameworks, continued innovation in formulation and strain development suggests a bright future for this mycoinsecticide in sustainable agriculture.

References#

1. Zare, R. & Gams, W. (2001). A revision of Verticillium sect. Prostrata. III. Generic classification. Nova Hedwigia, 72(3–4), 329–337. DOI: 10.1127/nova.hedwigia/72/2001/329
2. Vu, V. H., Hong, S. I., & Kim, K. (2007). Selection of entomopathogenic fungi for aphid control. Journal of Bioscience and Bioengineering, 104(6): 498–505. https://doi.org/10.1263/jbb.104.498
3. Nicoletti, R., & Becchimanzi, A. (2020). Endophytism of Lecanicillium and Akanthomyces. Agriculture, 10(6), 205. https://doi.org/10.3390/agriculture10060205
4. Fadayivata, S., Moravvej, G., & Karimi, J. (2014). Pathogenicity of the fungus Lecanicillium longisporum against Sipha maydis and Metopolophium dirhodum in laboratory conditions. Journal of Plant Protection Research, 54(1), 67–73. https://doi.org/10.2478/jppr-2014-0010
5. Copping, L. G., & Menn, J. J. (2000). Biopesticides: A review of their action, applications and efficacy. Pest Management Science, 56(8), 651–676. http://dx.doi.org/10.1002/1526-4998(200008)56:8%3C651::AID-PS201%3E3.0.CO;2-U
6. Dara, S. K. (2019). Non‑Entomopathogenic Roles of Entomopathogenic Fungi in Promoting Plant Health and Growth. Insects, 10(9): 277. https://doi.org/10.3390/insects10090277
7. Vega, F. E. (2018). The use of fungal entomopathogens as endophytes in biological control—a review. Mycologia, 110(1), 4–30. https://doi.org/10.1080/00275514.2017.1418578
8. Zimmermann, G. (2007). Review on safety of entomopathogenic fungi to non-target organisms. Biocontrol Science and Technology, 17(9), 879–920. https://doi.org/10.1080/09583150701593963