Fungal Allies Combat Stink Bugs in Beans

Jim Crocker
25th April, 2024

Fungal Allies Combat Stink Bugs in Beans

Image Source: Natural Science News, 2024

Key Findings

  • In Latin America, Cuban strains of the fungus Beauveria bassiana effectively kill harmful stink bugs on beans
  • The fungus infects bugs through their shell, multiplies inside, and causes death, offering an eco-friendly pest control method
  • Tests in semi-field conditions show the fungus could be integrated into pest management, reducing reliance on chemical pesticides
Stink bugs are notorious for their destructive impact on various crops, including the common bean—a staple food in many parts of the world. In the fight against these pests, scientists are seeking alternatives to synthetic chemical insecticides, which pose risks to human health and the environment. The latest research from Universidad Michoacana de San Nicolás de Hidalgo offers promising insights into the use of a biological agent to control stink bug populations[1]. The study focuses on two species of stink bugs, Nezara viridula and Piezodorus guildinii, which are particularly harmful in Latin America. Researchers evaluated the effectiveness of two Cuban strains of Beauveria bassiana, a fungus known to infect and kill insects, as well as a commercially available Cuban strain. The concentration of fungal spores used in the tests was 1 × 10^8 conidia/ml, which is a measure of the number of fungal particles in a liquid. Beauveria bassiana works by infecting the stink bugs through their cuticle—their outer shell. Once inside, the fungus multiplies, ultimately causing the death of the insect. This method of biological control is considered environmentally friendly and specific to the target pest, reducing the collateral damage seen with broad-spectrum insecticides. The study's experiments were conducted both in controlled settings using Petri dishes and in semi-field conditions to simulate a more natural environment. The goal was to determine the mortality rate of the stink bugs and the median Lethal Time (LT50), which is the time it takes for half the population of bugs to die after treatment. Previous studies have highlighted the challenges of managing stink bug populations. For instance, the reliance on chemical insecticides is not sustainable due to the risks and the development of pesticide resistance[2]. Moreover, stink bugs have shown varying susceptibility to Beauveria bassiana, influenced by factors such as the secretion of defensive chemicals that can inhibit fungal growth[3]. The production and formulation of Beauveria bassiana as a biocontrol agent have been a bottleneck in its widespread adoption. However, advancements in fermentation technology and the development of robust formulations are making it a more viable option[4]. Additionally, the timing of crop planting can influence stink bug populations, as demonstrated by field experiments that showed fluctuating densities and damage levels across different planting dates[5]. The findings from the Universidad Michoacana de San Nicolás de Hidalgo study are significant as they indicate that the Cuban strains of Beauveria bassiana are effective in killing the stink bugs. The results from the semi-field experiment are particularly encouraging, suggesting that the fungus could be used as part of an integrated pest management strategy. The study builds on previous research by not only demonstrating the potential of Beauveria bassiana as a biocontrol agent but also by showcasing the effectiveness of specific strains against the most damaging stink bug species in Latin America. This research ties together past findings, expanding on the knowledge of biological control methods and their practical applications. By offering an alternative to chemical pesticides, the study supports the shift towards more sustainable agriculture. The success of Beauveria bassiana against stink bugs could lead to safer food production, reduced environmental impact, and a new way for farmers to protect their crops from these pervasive pests.

AgricultureBiotechEcology

References

Main Study

1) Biological control potential of two Beauveria bassiana isolates against the stink bugs Nezara viridula L. and Piezodorus guildinii Westwood (Hemiptera: Pentatomidae) in common bean

Published 23rd April, 2024

https://doi.org/10.1186/s41938-024-00787-3

Related Studies

2) Natural Enemies and Biological Control of Stink Bugs (Hemiptera: Heteroptera) in North America.

https://doi.org/10.3390/insects13100932

3) The fungistatic and fungicidal effects of volatiles from metathoracic glands of soybean-attacking stink bugs (Heteroptera: Pentatomidae) on the entomopathogen Beauveria bassiana.

https://doi.org/10.1016/j.jip.2015.08.011

4) The production and uses of Beauveria bassiana as a microbial insecticide.

https://doi.org/10.1007/s11274-016-2131-3

5) Seeding Dates and Cultivars Effects on Stink Bugs Population and Damage on Common Bean Phaseolus vulgaris L.

https://doi.org/10.1007/s13744-017-0512-4


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