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Experimental epizootiology of Zoophthora anhuiensis (Entomophthorales) against Myzus persicae (Homoptera: Aphididae) with a description of a modified Gompertz model for aphid epizootics
Author(s) -
Feng MingGuang,
Li HuiPing
Publication year - 2003
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1046/j.1462-2920.2003.00529.x
Subject(s) - myzus persicae , biology , entomophthorales , epizootiology , aphididae , epizootic , aphid , homoptera , horticulture , botany , conidium , pest analysis , virology , outbreak
Summary Epizootiological features of Zoophthora anhuiensis , a fungal pathogen specific to aphids in southern China, were studied in six aptera colonies of Myzus persicae at 16 regimes of temperature ( T = 10, 15, 20 and 25°C) and relative humidity ( H = 90%, 95%, 98% and 100% RH) with initially infected proportion ( I p ) of 0.5 in experiment (Expt) 1 or at a fixed regime of 15°C and 100% RH with a variable I p of 0.17–1.00 in Expt 2. Mycosis‐caused mortalities ( M p ) varied with aphid densities ( D ) over time after colony initiation ( t ) were well fitted to a Gompertz growth model modified to include the variables T , H , I p and D in the form of M p = 91.72exp{−5.282exp[–(0.0095 T + 0.0128 H / T −0.5407 D 2 / H ) t ]} for Expt 1 ( r 2 = 0.94) or M p = 95.49exp{−4.314exp[–(0.1479 I p + 0.1636/ D ) t ]} for Expt 2 ( r 2 = 0.97). These variables were effective in determining the rate of epizootic development in the M. persicae colonies. Based on the observed and fitted results, Z. anhuiensis was most adaptive to cool climate or season and epizootiologically was subject to a minimal effect of RH at an optimum of ≈ 15°C. However, the humidity became determinant for epizootic progress at higher temperatures. Interactive effects of the variables and application of the fitted models for predicting epizootic development in field situations are discussed.