Native Wasps Could Help Control Pests in Cabbage and Broccoli Crops

Jenn Hoskins
26th July, 2024

Native Wasps Could Help Control Pests in Cabbage and Broccoli Crops

Image Source: Natural Science News, 2024

Key Findings

  • Researchers from the University of Otago studied the effectiveness of native North American wasps in controlling caterpillars on Brassica crops like broccoli and kale
  • Polistes metricus was 100% effective at removing caterpillars and significantly reduced plant damage in a controlled environment
  • Polistes fuscatus removed over 80% of caterpillars within three hours, suggesting these wasps could be a sustainable alternative to chemical pesticides
Social paper wasps, specifically Polistes metricus and Polistes fuscatus, have shown significant potential as natural biocontrol agents for agricultural pests. Researchers from the University of Otago conducted a study to evaluate the effectiveness of these native North American wasps in controlling lepidopteran larvae, which are known to cause substantial damage to Brassica crops such as broccoli and kale[1]. In the first part of the study, P. metricus was translocated to one-half of a divided screened hoop house, while a mix of 4th-5th instar lepidopteran larvae (Trichoplusia ni, Pieris spp., and Plutella xylostella) were placed on half of the broccoli plants on both sides of the hoop house. The researchers recorded and replaced missing caterpillars daily and assessed leaf damage after one week. Remarkably, P. metricus was 100% effective at removing all caterpillars from the wasp side of the hoop house, and plant damage by caterpillars was significantly reduced in the presence of wasps. The second part of the study replicated these conditions using P. fuscatus and kale plants with a 2 × 2 experimental design. This setup included plants with or without T. ni larvae and either covered with insect mesh or left exposed. By the second day, P. fuscatus removed over 80% of the larvae within three hours of their placement on the plants. These results suggest that native Polistes wasps could be an effective component of integrated pest management strategies. This study builds on previous research highlighting the ecological roles and benefits of social wasps. For instance, it has been noted that social wasps, including aculeate wasps, provide essential ecosystem services such as natural pest management and biological control[2]. This aligns with findings that social wasps capture a significant percentage of leaf-eating caterpillars in small farms and urban gardens, thereby reducing the need for chemical pesticides and their associated environmental impacts[3]. The University of Otago study also ties into broader research on the behavioral ecology of wasps. For example, nutritional physiology and nutrient signaling pathways, such as the insulin pathway, have been shown to regulate foraging behavior in social insects, including wasps[4]. This study provides further evidence that nutritional asymmetries among individuals influence the division of labor in eusocial societies, which can be leveraged for pest control. In conclusion, the research from the University of Otago demonstrates that Polistes metricus and Polistes fuscatus can effectively reduce caterpillar populations and associated plant damage in Brassica crops. This supports the potential use of these native wasps as a sustainable alternative to chemical pesticides, aligning with the broader understanding of the ecological and economic benefits provided by social wasps.

AgricultureEnvironmentAnimal Science

References

Main Study

1) Native Polistes wasps (Hymenoptera: Vespidae) hold potential as biocontrol agents for lepidopteran pests of Brassica.

Published 24th July, 2024

https://doi.org/10.1093/jee/toae146

Related Studies

2) Ecosystem services provided by aculeate wasps.

https://doi.org/10.1111/brv.12719

3) Pest Control Potential of Social Wasps in Small Farms and Urban Gardens.

https://doi.org/10.3390/insects10070192

4) Nutrition and division of labor: Effects on foraging and brain gene expression in the paper wasp Polistes metricus.

https://doi.org/10.1111/j.1365-294X.2011.05344.x


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