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Living on the Edges: Spatial Niche Occupation of Asian Citrus Psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), in Citrus Groves.

Sétamou M, Bartels DW - PLoS ONE (2015)

Bottom Line: In both cultivars, significantly more psyllids were found on perimeter trees throughout the study period suggesting a strong edge effect in D. citri distribution in the groves.Citrus groves located at the outer edge of the study with at least one side non-surrounded to other citrus groves harbored significantly more D. citri than groves located within the block cluster and entirely surrounded by other groves.In addition, psyllid densities decreased significantly with increasing distance from the grove edge.

View Article: PubMed Central - PubMed

Affiliation: Department of Agriculture, Agribusiness and Environmental Sciences, Texas A&M University-Kingsville Citrus Center, Weslaco, Texas, United States of America.

ABSTRACT
The spatial niche occupation of the Asian citrus psyllid, Diaphorina citri Kuwayama, 1908, was evaluated to determine its field colonization and food resource exploitation strategies in citrus groves. Mature grapefruit and sweet orange groves were surveyed as part of an area-wide program in 2009-2010 to determine D. citri population densities and between-tree distribution. In both cultivars, significantly more psyllids were found on perimeter trees throughout the study period suggesting a strong edge effect in D. citri distribution in the groves. D. citri densities and infestation levels gradually declined from the edge to the center of grove. Higher numbers of D. citri were recorded on trees located on the east and south sides of the groves than those on the west and north sides. Citrus groves located at the outer edge of the study with at least one side non-surrounded to other citrus groves harbored significantly more D. citri than groves located within the block cluster and entirely surrounded by other groves. In detailed field studies during 2012, infestation of D. citri started from border trees in the grove where possibly one generation is completed before inner trees become infested. In addition, psyllid densities decreased significantly with increasing distance from the grove edge. Using the selection index, D citri exhibited a strong niche occupation preference for border trees.

No MeSH data available.


Related in: MedlinePlus

Diaphorina citri flush shoot infestation levels and population fluctuations on citrus trees depending on their position in the grove during area-wide surveys (2009–2010).
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pone.0131917.g001: Diaphorina citri flush shoot infestation levels and population fluctuations on citrus trees depending on their position in the grove during area-wide surveys (2009–2010).

Mentions: Densities of all D. citri life stages and flush shoot infestation levels on citrus greatly varied with sampling time (F > 32.46; df = 1, 35,000, P < 0.0001; Table 1, Fig 1) and the phenology of citrus trees. Four major flush cycles were observed in the groves during the survey period: February-March, May-June, July-August and September-October. Psyllid populations increased during flush cycles when new flush shoots were produced by trees and declined thereafter. There was a gradual increase in flush shoot infestation levels by D. citri in citrus groves from February to September-October when peak infestation levels were observed in Texas, but lower infestation levels were observed during the flush cycle of July-August before dramatically increasing during the last flush of the fall flush cycle in September-October (Fig 1). Despite this trend of gradual increase in flush shoot infestation levels with time during flush cycles, D. citri densities on flush shoots did not show a pattern of gradual increase, with the exception of adult numbers in sweet orange groves. Egg densities recorded on flush shoots during the summer flush cycles in June-August were significantly lower than those observed during any other flush cycle, while densities of nymphs were lowest during the summer flush cycle (July-August) in both citrus cultivars. The highest densities of all D. citri life stages were observed during the fall flush cycle in September-October (Fig 1).


Living on the Edges: Spatial Niche Occupation of Asian Citrus Psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), in Citrus Groves.

Sétamou M, Bartels DW - PLoS ONE (2015)

Diaphorina citri flush shoot infestation levels and population fluctuations on citrus trees depending on their position in the grove during area-wide surveys (2009–2010).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507854&req=5

pone.0131917.g001: Diaphorina citri flush shoot infestation levels and population fluctuations on citrus trees depending on their position in the grove during area-wide surveys (2009–2010).
Mentions: Densities of all D. citri life stages and flush shoot infestation levels on citrus greatly varied with sampling time (F > 32.46; df = 1, 35,000, P < 0.0001; Table 1, Fig 1) and the phenology of citrus trees. Four major flush cycles were observed in the groves during the survey period: February-March, May-June, July-August and September-October. Psyllid populations increased during flush cycles when new flush shoots were produced by trees and declined thereafter. There was a gradual increase in flush shoot infestation levels by D. citri in citrus groves from February to September-October when peak infestation levels were observed in Texas, but lower infestation levels were observed during the flush cycle of July-August before dramatically increasing during the last flush of the fall flush cycle in September-October (Fig 1). Despite this trend of gradual increase in flush shoot infestation levels with time during flush cycles, D. citri densities on flush shoots did not show a pattern of gradual increase, with the exception of adult numbers in sweet orange groves. Egg densities recorded on flush shoots during the summer flush cycles in June-August were significantly lower than those observed during any other flush cycle, while densities of nymphs were lowest during the summer flush cycle (July-August) in both citrus cultivars. The highest densities of all D. citri life stages were observed during the fall flush cycle in September-October (Fig 1).

Bottom Line: In both cultivars, significantly more psyllids were found on perimeter trees throughout the study period suggesting a strong edge effect in D. citri distribution in the groves.Citrus groves located at the outer edge of the study with at least one side non-surrounded to other citrus groves harbored significantly more D. citri than groves located within the block cluster and entirely surrounded by other groves.In addition, psyllid densities decreased significantly with increasing distance from the grove edge.

View Article: PubMed Central - PubMed

Affiliation: Department of Agriculture, Agribusiness and Environmental Sciences, Texas A&M University-Kingsville Citrus Center, Weslaco, Texas, United States of America.

ABSTRACT
The spatial niche occupation of the Asian citrus psyllid, Diaphorina citri Kuwayama, 1908, was evaluated to determine its field colonization and food resource exploitation strategies in citrus groves. Mature grapefruit and sweet orange groves were surveyed as part of an area-wide program in 2009-2010 to determine D. citri population densities and between-tree distribution. In both cultivars, significantly more psyllids were found on perimeter trees throughout the study period suggesting a strong edge effect in D. citri distribution in the groves. D. citri densities and infestation levels gradually declined from the edge to the center of grove. Higher numbers of D. citri were recorded on trees located on the east and south sides of the groves than those on the west and north sides. Citrus groves located at the outer edge of the study with at least one side non-surrounded to other citrus groves harbored significantly more D. citri than groves located within the block cluster and entirely surrounded by other groves. In detailed field studies during 2012, infestation of D. citri started from border trees in the grove where possibly one generation is completed before inner trees become infested. In addition, psyllid densities decreased significantly with increasing distance from the grove edge. Using the selection index, D citri exhibited a strong niche occupation preference for border trees.

No MeSH data available.


Related in: MedlinePlus