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Temporal and Spatial Development of Papaya Ringspot in Veracruz, Mexico
Author(s) -
MoraAguilera Gustavo,
Téliz Daniel,
Campbell C. Lee,
Avila Catarino
Publication year - 1992
Publication title -
journal of phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 60
eISSN - 1439-0434
pISSN - 0931-1785
DOI - 10.1111/j.1439-0434.1992.tb01278.x
Subject(s) - biology , quadrat , aphid , myzus persicae , population , aphis gossypii , carica , veterinary medicine , spatial distribution , common spatial pattern , gompertz function , botany , horticulture , ecology , aphididae , pest analysis , homoptera , statistics , mathematics , demography , medicine , shrub , sociology
The temporal progress and spatial distribution of papaya ringspot virus (PRV) and populations of aphid vectors were monitored in two papaya ( Carica papaya ) plantations in the state of Veracruz, México. The incidence of PRV had a typical sigmoidal curve and the logistic model was more acceptable for describing the disease progress than the Gompertz model. The rate (r L of increase in disease incidence (0.034 and 0.023/unit/day in Plot A and B, respectively) differed (P = 0.05) between the plots; differences in number of aphids trapped could account for the difference. The initial determination of an apparent regular spatial pattern early in the epidemic, obtained with a quadrat size determined by Greig‐Smith's method (n = 8 plants/quadrat) at 50 % disease incidence, was inconsistent with our biological observations in the field. An arbitrarily selected, square quadrat size (n = 9 plants/quadrat), was more consistent with visual observation for describing the spatial pattern in the field. With 9 plants/quadrat a random pattern was found. Aphid populations had a bimodal distribution at both sites with the highest population peak in December–February and a secondary peak in August–September and change in disease incidence was generally related to the aphid population level in the previous month. None of the five potential aphid vectors ( Myzus persicae , Aphis gossypii A. nerii , A. citricola and Macrosiphon euphorbiae ) of PRV in Mexico colonized the papaya plants, however, which may explain the absence of clustering of disease.