Effects of Gender, Origin, and Age on Transmission ofXylella fastidiosato Grapevines byHomalodisca vitripennis(Hemiptera: Cicadellidae)

Abstract

Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae) is an invasive vector of Xylella fastidiosa, the causal agent of Pierce's disease of grapevines (Vitis vinifera L.). Transmission efficiency of X. fastidiosa to grapevines by H. vitripennis originating from two geographically separated populations in California (Riverside and Bakersfield) based on gender and age was evaluated. To evaluate transmission efficiencies among groups, insects were given a 96-h acquisition access period on infected grapevines and caged in groups of five on healthy grapevines for a 72-h inoculation access period. At the conclusion of tests, polymerase chain reaction determined that a mean ± SD of 0.98 ± 1.02 X. fastidiosa-positive H. vitripennis were present on each grapevine and that 29% of test plants were infected. Acquisition and retention of X. fastidiosa was not affected by vector origin, gender, or age. The probability that a grapevine was infected 12 wk after the inoculation access period increased with the number of X. fastidiosa-positive H. vitripennis per plant. Gender had no effect on inoculation success and main effects of insect origin and age on inoculation success were minor. Collectively, the result indicated that H. vitripennis origin, gender, and age did not affect acquisition and retention of X. fastidiosa and had only minor effects on inoculation success under laboratory conditions. Accordingly, rates of pathogen spread in the field are more likely to be affected by local biotic and abiotic factors that differentially affect H. vitripennis abundance and movement based on origin, gender, and age than inherent differences in transmission efficiencies among these groups.

Genomic Insights into Xylella fastidiosa Interactions with Plant and Insect Hosts

“…Thus, host plants harboring larger X. fastidiosa populations generally result in higher transmission efficiency, and vice versa. Vector age and sex do not affect overall transmission efficiency (Krugner et al 2012). …”

Plant Water Stress Effects on the Net Dispersal Rate of the Insect Vector <I>Homalodisca vitripennis</I> (Hemiptera: Cicadellidae) and Movement of Its Egg Parasitoid, <I>Gonatocerus ashmeadi</I> (Hymenoptera: Mymaridae)

“…Using absolute H. vitripennis population density data (Ϸ6,352 individuals per tree) obtained by Coviella et al (2006) from an untreated citrus orchard, we estimate that under the conditions described herein, Ϸ708,883 H. vitripennis individuals (6,352 individuals per tree ϫ 360 trees ϫ 0.31 ϭ 708,883 individuals) emigrated to adjacent landscapes over the two-month sampling period. In a situation where: 1) only emigration occurs; 2) transmission efÞciency of X. fastidiosa is 20% (Purcell and Saunders 1999;Costa et al 2000Costa et al , 2006Almeida and Purcell 2003a,b;Damsteegt et al 2006, Krugner et al 2012; 3) all emigrant individuals carry X. fastidiosa; and 4) redistribution in the adjacent vineyard is uniform at one vector per vine, it is estimated that Ϸ141,777 grapevines would be infected by the pathogen during the 2-mo period. Clearly, management strategies aimed at reducing H. vitripennis emigration and population density in citrus orchards can affect disease incidence in adjacent vineyards.…”

“…Infested citrus orchards can act as a source of vectors to adjacent vineyards as a result of the movement of H. vitripennis between these two crops (Blua and Morgan 2003), which affects PD incidence (Perring et al 2001, Park et al 2006. Laboratory studies and epidemiological models suggest that in addition to vector population density, vector mobility and pathogen transmission efÞciency are key factors affecting rates of X. fastidiosa spread (Jeger et al 1998, Sisterson 2008, Daugherty and Almeida 2009, Krugner et al 2012. Transmission efÞciency of X. fastidiosa by H. vitripennis has been quantiÞed in numerous studies (Purcell and Saunders 1999;Costa et al 2000Costa et al , 2006Almeida and Purcell 2003a,b;Damsteegt et al 2006;Krugner et al 2012).…”

“…Laboratory studies and epidemiological models suggest that in addition to vector population density, vector mobility and pathogen transmission efÞciency are key factors affecting rates of X. fastidiosa spread (Jeger et al 1998, Sisterson 2008, Daugherty and Almeida 2009, Krugner et al 2012. Transmission efÞciency of X. fastidiosa by H. vitripennis has been quantiÞed in numerous studies (Purcell and Saunders 1999;Costa et al 2000Costa et al , 2006Almeida and Purcell 2003a,b;Damsteegt et al 2006;Krugner et al 2012). Similarly, methods to estimate H. vitripennis population densities are also available (Coviella et al 2006, Naranjo andCastle 2010).…”

Host plants mixture and fitness ofKolla paulula: with an evaluation of the application of Weibull function

“…; Krugner et al. ). Although PD was identified in Taiwan in 2002, none of the known vector species have been found in Taiwan (Su et al.…”