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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Insects and Horticulture Research » Research » Publications at this Location » Publication #222405
Title: Dispersion patterns and sampling plans for Diaphorina citri (Hemiptera: Psyllidae) in citrus

Author
item SETAMOU, MAMOUDOU - TEXAS A&M UNIVERSITY
item FLORES, DANIEL - APHIS
item FRENCH, J. VICTOR - TEXAS A&M UNIVERSITY
item Hall, David

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/14/2008
Publication Date: 8/10/2008
Citation: Setamou, M., Flores, D., French, J., Hall, D.G. 2008. Dispersion patterns and sampling plans for Diaphorina citri (Hemiptera: Psyllidae) in citrus. Journal of Economic Entomology. 101:1478-1487.

Interpretive Summary: The abundance and spatial dispersion of the Asian citrus psyllid were studied in grapefruit and sweet orange orchards. Although flush shoot infestation levels did not vary with host plant species, densities of immature and adults were significantly higher on sweet orange than on grapefruit. Immatures were found in significantly higher numbers in the south-eastern quadrant of trees than other parts of the canopy. The field dispersion patterns of eggs, nymphs, and adults were aggregated among flush shoots in individual trees. The minimum number of flush shoots per tree needed to estimate densities varied from 8 for eggs to 4 flush shoots for adults. Projections indicated that a sampling plan consisting of 10 trees and 8 flush shoots per tree would provide density estimates acceptable enough for population studies and management decisions. A presence-absence sampling plan was developed and can be used to provide a quick estimate of population densities in citrus.

Technical Abstract: The abundance and spatial dispersion of the Asian citrus psyllid, Diaphorina citri Kuwayama, were studied in thirty-four grapefruit (Citrus × paradisi) and six sweet orange (Citrus sinensis) orchards from March to August 2006 when the pest is more abundant in southern Texas. Although flush shoot infestation levels did not vary with host plant species, densities of D. citri eggs, nymphs and adults were significantly higher on sweet orange than on grapefruit. D. citri immatures were also found in significantly higher numbers in the south-eastern quadrant of trees than other parts of the canopy. The spatial distribution of nymphs and adults was analyzed using Iowa’s patchiness regression and Taylor’s power law. Taylor’s power law fitted the data better than Iowa’s model. Based on both regression models, the field dispersion patterns of D. citri eggs, nymphs, and adults were aggregated among flush shoots in individual trees as indicated by the regression slopes that were significantly > 1. The minimum number of flush shoots per tree needed to estimate D. citri densities varied from 8 for eggs to 4 flush shoots for adults. Projections indicated that a sampling plan consisting of 10 trees and 8 flush shoots per tree would provide density estimates of the three developmental stages of D. citri acceptable enough for population studies and management decisions. A presence-absence sampling plan with a fixed-precision-level was developed and can be used to provide a quick estimation of D. citri populations in citrus orchards.