Studying a Fungus That Targets and Controls Mealybugs

Greg Howard
3rd July, 2024

Studying a Fungus That Targets and Controls Mealybugs

Highlighting the strong pathogenicity of Aspergillus parasiticus (strain ZHKUAP1), the Egyptian mealybug (Icerya aegyptiaca) progressed from a healthy state (a) to showing wax degradation (b) and extensive mycelial growth (c) until fully covered by conidia (d).

Image adapted from: Wei et al. / CC BY (Source)

Key Findings

  • Researchers in China isolated a fungus, Aspergillus parasiticus ZHKUAP1, from the Egyptian mealybug on the parasol leaf tree
  • The fungus was highly effective in killing the mealybugs in lab tests, showing significant mortality rates
  • Field trials confirmed that A. parasiticus ZHKUAP1 effectively reduced the mealybug population, offering a promising biocontrol method
The Egyptian mealybug, Icerya aegyptiaca, is a significant agricultural pest known for its protective wax shell, which makes it difficult for conventional insecticides to be effective. Recently, researchers at Zhongkai University have explored a novel biocontrol method to combat this pest by isolating an entomogenous fungus from I. aegyptiaca on the parasol leaf tree, Macaranga tanarius, in China[1]. This study aimed to evaluate the effectiveness of the fungus in reducing the population of I. aegyptiaca. The isolated fungus was identified as Aspergillus parasiticus through morphological and phylogenetic analyses and was named ZHKUAP1. The researchers assessed the biological characteristics, pathogenicity, and field control efficacy of this strain. The findings indicate that A. parasiticus ZHKUAP1 holds promise as a biocontrol agent against the Egyptian mealybug. This research builds on previous studies that have explored biocontrol methods for various pests. For instance, a study identified Metarhizium pingshaense as an effective fungal pathogen against the polyphagous pest Conogethes punctiferalis, showing high mortality rates and potential for development as a mycoinsecticide[2]. This earlier work underscores the potential of fungal pathogens in pest management, providing a foundation for the current study on I. aegyptiaca. Another relevant study investigated the use of plant essential oils to enhance the effectiveness of botanical insecticides against I. aegyptiaca. The combination of rosehip oil (Ro) and matrine demonstrated strong insecticidal activity by penetrating the pest's wax shell, thereby improving control efficacy[3]. This study highlights the challenges of controlling pests with protective barriers and the innovative approaches being explored to overcome them. In the current study, A. parasiticus ZHKUAP1 was evaluated for its pathogenicity against I. aegyptiaca. The researchers conducted bioassays to determine the fungus's ability to infect and kill the mealybugs. The results showed significant mortality rates, indicating that ZHKUAP1 is a potent pathogen for I. aegyptiaca. Additionally, field trials were conducted to assess the practical application of this biocontrol method. The field results confirmed that A. parasiticus ZHKUAP1 effectively reduced the population of I. aegyptiaca, demonstrating its potential for use in integrated pest management programs. The study's findings are particularly significant given the difficulties in controlling I. aegyptiaca with traditional insecticides. The protective wax shell of the mealybug often renders chemical treatments ineffective. By contrast, the fungal pathogen A. parasiticus ZHKUAP1 can penetrate this barrier and infect the pest, offering a more efficient and environmentally friendly solution. In summary, the research conducted by Zhongkai University provides promising evidence for the use of Aspergillus parasiticus ZHKUAP1 as a biocontrol agent against the Egyptian mealybug. This study not only expands on previous findings regarding the potential of fungal pathogens in pest management[2] but also addresses the specific challenges posed by pests with protective barriers[3]. As the agricultural industry continues to seek sustainable and effective pest control methods, the development of biocontrol fungi like A. parasiticus ZHKUAP1 represents a significant step forward.

BiochemAnimal ScienceMycology

References

Main Study

1) Isolation, identification, biological characteristics, and pathogenicity of an entomogenous fungus against the Egyptian mealybug, Icerya aegyptiaca (J.) (Hemiptera: Monophlebidae)

Published 2nd July, 2024

https://doi.org/10.1186/s41938-024-00802-7

Related Studies

2) Characterization and biocontrol potential of a naturally occurring isolate of Metarhizium pingshaense infecting Conogethes punctiferalis.

https://doi.org/10.1016/j.micres.2020.126645

3) The synergistic effects of rosehip oil and matrine against Icerya aegyptiaca (Douglas) (Hemiptera: Coccoidea) and the underlying mechanisms.

https://doi.org/10.1002/ps.6983


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