New Sampling Plan to Classify Thrips Populations in Onion Fields

Jim Crocker
20th July, 2024

New Sampling Plan to Classify Thrips Populations in Onion Fields

Image Source: Natural Science News, 2024

Key Findings

  • The study was conducted in 24 commercial onion fields in New York during 2021 and 2022
  • Researchers developed a new sampling plan that uses fewer samples to classify thrips populations as above or below management thresholds
  • The new plan required 78% fewer samples on average compared to traditional methods, saving time and labor for growers
Onion thrips, Thrips tabaci Lindeman, are a significant pest that inflicts economic damage on onion crops by reducing bulb yields and transmitting plant pathogens. Traditionally, growers have managed thrips infestations using insecticides based on action thresholds that involve visually counting thrips on a fixed number of onion plants per field. However, this method is inefficient, particularly when thrips populations are significantly above or below the action threshold. Researchers at Cornell University aimed to address this inefficiency by developing a sequential sampling plan that could quickly and reliably classify thrips populations in commercial onion fields as above or below specified management thresholds[1]. The study was conducted in 24 commercial onion fields in New York during 2021 and 2022. The researchers utilized Taylor's power law and Wald's Sequential Probability Ratio Test to develop the sampling plans. These statistical tools help determine the relationship between sample size and population density, and assess the probability that a given sample reflects the true population status, respectively. To validate the efficacy of the new sampling plan, the researchers used both simulated and historical field data of thrips populations. The results were promising: the sequential sampling plan required an average of 78% fewer samples to make a control decision compared with the traditional fixed-sampling approach. Specifically, treatment decisions were reached in 72% of cases after inspecting only 10 plants, while only 6% of cases required examining more than 25 plants. Comparisons with fixed-sample sizes ranging from 23 to 68 plants revealed a 96% agreement in decision-making and a 78% reduction in sampling effort when using the sequential sampling plans. This study builds upon earlier work in the field of pest management. For instance, the development of the "Sampling" iOS application for assessing disease and insect pest incidence using sequential sampling plans has already demonstrated the potential for such methods to save time and labor in field scouting[2]. Similarly, the research on soybean aphid sampling plans highlighted the benefits of using sequential sampling for efficient pest management, showing that binomial plans can significantly reduce the number of samples needed while maintaining decision accuracy[3]. The findings from the current study on onion thrips further validate the effectiveness of sequential sampling plans in agricultural pest management. Moreover, the research aligns with previous studies on the temporal dynamics of pests and their impact on crop yields. For instance, a study on onion thrips and iris yellow spot virus (IYSV) found that managing thrips populations before harvest and considering the spatial arrangement of fields based on harvest dates could mitigate the spread of IYSV[4]. The current study’s focus on rapid and reliable classification of thrips populations can contribute to more timely and effective pest management strategies, potentially reducing the spread of associated pathogens. In conclusion, the sequential sampling plan developed by Cornell University researchers represents a significant advancement in the efficient management of onion thrips. By reducing the number of samples needed to make control decisions, this method saves time and labor for growers while maintaining high decision accuracy. This study not only builds on but also extends the findings of previous research, demonstrating the broad applicability and benefits of sequential sampling plans in integrated pest management.

AgriculturePlant ScienceAnimal Science

References

Main Study

1) Development of a sequential sampling plan for classifying Thrips tabaci (Thysanoptera: Thripidae) populations in onion fields.

Published 19th July, 2024

https://doi.org/10.1093/jee/toae161

Related Studies

2) Sampling, a New iOS Application for Assessment of Damage by Diseases and Insect Pests Using Sequential Sampling Plans.

https://doi.org/10.1094/PDIS-04-22-0800-SR

3) Enumerative and binomial sequential sampling plans for soybean aphid (Homoptera: Aphididae) in soybean.

Journal: Journal of economic entomology, Issue: Vol 97, Issue 6, Dec 2004

4) Temporal dynamics of iris yellow spot virus and its vector, Thrips tabaci (Thysanoptera: Thripidae), in seeded and transplanted onion fields.

https://doi.org/10.1603/EN09165


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