Effective biopesticide and mite treatment for controlling thrips in strawberries

Chilli thrips, scientifically known as Scirtothrips dorsalis Hood, have become a significant invasive pest affecting strawberry crops in the United States. The University of Florida conducted a two-year field study from 2021 to 2023 to evaluate the effectiveness of a biopesticide and a thrips predator, Amblyseius swirskii, compared to traditional synthetic insecticides for managing this pest^[1]. This study aimed to find sustainable and effective alternatives to synthetic insecticides, which are commonly used but face issues such as pest resistance.

The study tested four different treatments in field-grown strawberries: (1) a biopesticide composed of capsicum oleoresin extract, garlic oil, and canola oil applied at the maximum label rate; (2) the predatory mite A. swirskii released at 30 predators per plot; (3) spinetoram, a synthetic insecticide, applied at the maximum label rate; and (4) a combination of the biopesticide applied 24 hours before releasing A. swirskii. A control plot with no insecticide or predatory mite releases was also maintained.

The results showed that the capsicum extract biopesticide could effectively manage S. dorsalis, especially during the latter stages of the strawberry field season when resistance to spinetoram is high. This finding is significant as it offers a potential alternative to synthetic insecticides, which are increasingly facing resistance issues from pests. The use of biopesticides aligns with the growing demand for more sustainable and environmentally friendly pest control methods.

However, the field performance of A. swirskii was variable. This variability suggests that while A. swirskii has potential as a biological control agent, more research is needed to understand the factors that affect its efficacy in the field. This aligns with previous research indicating that the performance of biological control agents can be influenced by various factors such as environmental conditions and prey availability^[2].

Previous studies have shown that the reproductive and feeding habits of pests like S. dorsalis can vary significantly depending on the region and host plants^[3]. The current study's findings on the effectiveness of different treatments for managing S. dorsalis in strawberries are crucial for developing region-specific pest management strategies. Understanding the geographical and host-specific dynamics of S. dorsalis can help tailor more effective control measures.

Additionally, research on A. swirskii has shown that its population growth is highly dependent on temperature and food availability^[4]. The current study's variable results with A. swirskii could be due to fluctuations in these factors in the field. The mite's optimum temperature for population growth is between 20 and 32°C, and its performance can be significantly reduced outside this range^[4]. Therefore, environmental conditions during the study period could have impacted the effectiveness of A. swirskii as a biological control agent.

In conclusion, the University of Florida's study provides valuable insights into alternative pest management strategies for S. dorsalis in strawberries. The use of capsicum extract biopesticide shows promise, especially in combating resistance issues associated with synthetic insecticides. However, the variable performance of A. swirskii highlights the need for further research to optimize the use of biological control agents in the field. By integrating findings from previous studies, this research contributes to a more comprehensive understanding of pest management and offers potential pathways for sustainable agriculture.

References

Main Study

1) Field efficacy of a biopesticide and a predatory mite for suppression of Scirtothrips dorsalis (Thysanoptera: Thripidae) in strawberry.

Published 28th June, 2024

https://doi.org/10.1093/jee/toae144

Related Studies

2) Challenges facing arthropod biological control: identifying traits for genetic improvement of predators in protected crops.

https://doi.org/10.1002/ps.5857

3) Distribution of Scirtothrips dorsalis (Thysanoptera: Thripidae) cryptic species complex in the United States and reproductive host assessment of its dominant member.

https://doi.org/10.1093/jee/toad138

4) Life tables and development of Amblyseius swirskii (Acari: Phytoseiidae) at different temperatures.

https://doi.org/10.1007/s10493-010-9385-5

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