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<p>The guava psyllid <i>Triozoida limbata</i> (Hemiptera: Triozidae) is a significant pest in guava (<i>Psidium guajava</i>) orchards, causing extensive damage to foliage and reducing fruit productivity. The nymphal stage of <i>T. limbata</i> is particularly detrimental, as the nymphs feed on the sap of young leaves, leading to leaf curling, gall formation, and necrosis, which can substantially reduce photosynthetic capacity and overall plant vigor. For the development of an Integrated Pest Management (IPM) program, understanding the spatial distribution of these nymphs in orchards is essential. This study investigated the spatial distribution patterns of <i>T. limbata immatures</i> across eight guava cultivars in a commercial orchard. A total of 30 samplings were conducted over two growing seasons, and spatial aggregation was assessed using several indices, including the variance-to-mean ratio (I), Morisita Index (Iδ), Lloyd’s Mean Crowding (X), and Green’s Index (GI). The results demonstrated a consistent pattern of aggregation across all cultivars, with higher pest densities localized in specific areas of the orchard. The variance-to-mean ratio ranged from 1.27 to 738.47, confirming an aggregated distribution. The Morisita Index values varied from 2.60 to 56.00, reinforcing significant clustering. Lloyd’s Mean Crowding ranged between 0.44 and 1005.71, while Green’s Index values fluctuated from 0.13 to 1.00, indicating strong aggregation in certain regions of the orchard. The chi-square adherence test confirmed that 25 out of 30 samplings followed a negative binomial distribution, further supporting the aggregated spatial distribution pattern. These findings suggest that spatially focused pest management approaches could be more effective in reducing pesticide use and protecting natural enemies, contributing to more sustainable IPM practices. Further research should investigate the ecological factors influencing the aggregation behavior of <i>T. limbata</i> and validate these findings across different environmental conditions.</p>

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Spatial distribution and aggregation patterns of Triozoida limbata immatures in guava cultivars: implications for targeted pest management strategies

  • 期刊论文

  • 发表日期：

    2025年4月8日

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  • Isaias de Oliveira,
  • Manoel A. Uchoa,
  • Marcos Gino Fernandes,
  • Odival Faccenda,
  • Thiago Alexandre Mota,
  • Inessa Steffany Torres de Oliveira

摘要

The guava psyllid Triozoida limbata (Hemiptera: Triozidae) is a significant pest in guava (Psidium guajava) orchards, causing extensive damage to foliage and reducing fruit productivity. The nymphal stage of T. limbata is particularly detrimental, as the nymphs feed on the sap of young leaves, leading to leaf curling, gall formation, and necrosis, which can substantially reduce photosynthetic capacity and overall plant vigor. For the development of an Integrated Pest Management (IPM) program, understanding the spatial distribution of these nymphs in orchards is essential. This study investigated the spatial distribution patterns of T. limbata immatures across eight guava cultivars in a commercial orchard. A total of 30 samplings were conducted over two growing seasons, and spatial aggregation was assessed using several indices, including the variance-to-mean ratio (I), Morisita Index (Iδ), Lloyd’s Mean Crowding (X), and Green’s Index (GI). The results demonstrated a consistent pattern of aggregation across all cultivars, with higher pest densities localized in specific areas of the orchard. The variance-to-mean ratio ranged from 1.27 to 738.47, confirming an aggregated distribution. The Morisita Index values varied from 2.60 to 56.00, reinforcing significant clustering. Lloyd’s Mean Crowding ranged between 0.44 and 1005.71, while Green’s Index values fluctuated from 0.13 to 1.00, indicating strong aggregation in certain regions of the orchard. The chi-square adherence test confirmed that 25 out of 30 samplings followed a negative binomial distribution, further supporting the aggregated spatial distribution pattern. These findings suggest that spatially focused pest management approaches could be more effective in reducing pesticide use and protecting natural enemies, contributing to more sustainable IPM practices. Further research should investigate the ecological factors influencing the aggregation behavior of T. limbata and validate these findings across different environmental conditions.