Researchers have discovered a natural solution to safeguard eucalyptus forest plantations from the eucalyptus snout beetle, a notorious pest causing substantial harm to eucalypt trees. By identifying and characterizing a naturally occurring pathogenic fungi, scientists have successfully transformed it into a bio-pesticide for controlling beetle populations.
A recent study has confirmed the identification of the pathogenic fungi crucial for managing the beetle issue. The ongoing characterization process holds promise for safeguarding the country’s extensive 115,570 hectares of eucalyptus plantations.
The eucalyptus snout beetle (Gonipterus platensis) is recognized by the Food and Agriculture Organization of the United Nations as a leaf-feeding beetle and a significant defoliator of eucalyptus trees. Although native to Australia, this pest has spread to numerous countries where eucalypts are cultivated, causing damage by feeding on leaves, buds, and shoots, resulting in stunted growth and deflation, leading to substantial losses. Its ability to cover vast areas during transport of forest products exacerbates the problem.
Microwasps Anaphes spp have traditionally been employed as a costly solution to control the beetle. In response, scientists sought naturally occurring pathogenic fungi to address the issue more sustainably.
The researchers emphasized the beetle’s capacity to wreak havoc on eucalyptus, citing instances where its distribution expanded significantly within a short period. In 1998 alone, it spread across 1,156 square kilometers, increasing its range by 160 km per year in the United States and South Africa within the initial five years.
While mycoinsecticides from the fungal genera Beauveria and Metarhizium are commonly used for such purposes, limited research on entomopathogenic fungi targeting Gonipterus populations is available. The new research involves collecting fungi from naturally infected beetles, enhancing the pathogen’s adaptability to environmental conditions, thereby making it more effective in controlling beetles in forest populations.
The fungi derived from this research could be employed in developing a bio-pesticide for sustainable forestry practices through integrated pest management. Moreover, these fungi may prove beneficial in other regions where the eucalyptus snout beetle poses a significant threat.
Earlier investigations evaluated five biological insecticides, with Beauveria bassiana exhibiting high effectiveness, causing 100% mortality by contact and ingestion. The fungi Beauveria pseudobassiana and Metarhizium brunneum were identified as the most virulent, with B. pseudobassiana considered the most suitable for producing a bio-pesticide due to its adaptability and tolerance to environmental conditions.
Eucalyptus forests, covering approximately 20 million hectares globally, play a crucial role in paper pulp production. The study underscores the potential for eucalyptus snout beetles to cause severe defoliation and wood volume losses, emphasizing the necessity for effective control measures using both biological and chemical methods. The researchers have successfully developed the fungi by optimizing parameters such as insecticidal activity and UV-B radiation tolerance, ensuring their suitability for mass production and commercialization.