Feeding and development of the glassy-winged sharpshooter, Homalodisca vitripennis, on Australian native plant species and implications for Australian biosecurity.

In any insect invasion the presence or absence of suitable food and oviposition hosts in the invaded range is a key factor determining establishment success. The glassy-winged sharpshooter, Homalodisca vitripennis, is an important insect vector of the xylem-limited bacterial plant pathogen, Xylella fastidiosa, which causes disease in numerous host plants including food and feedstock crops, ornamentals and weeds. Both the pathogen and the vector are native to the Americas and are considered to be highly invasive. Neither has been detected in Australia. Twelve Australian native plant species present in the USA were observed over two years for suitability as H. vitripennis feeding, oviposition and nymph development hosts. Hosts providing evidence of adult or nymph presence were Leptospermum laevigatum, Acacia cowleana, Eremophila divaricata, Eucalyptus wandoo, Hakea laurina, Melaleuca laterita and Swainsona galegifolia. An oviposition-suitability field study was conducted with citrus, a favoured oviposition host, as a positive control. Citrus and L. laevigatum, A. cowleana, B. ericifolia×B. spinulosa, C. pulchella, E. divaricata, E. wandoo, H. laurina, and S. galegifolia were found to be oviposition hosts. Egg parasitism by the mymarid parasitoid Gonatocerus ashmeadi was observed on all Australian plants. A number of Australian plants that may facilitate H. vitripennis invasion have been identified and categorised as 'high risk' due to their ability to support all three life stages (egg, nymph and adult) of the insect in the field (L. laevigatum, A. cowleana, E. divaricata, H. laurina, and S. galegifolia). The implications of these host status and natural enemy research findings are discussed and placed in an Australian invasion context

Weekly <i>Homalodisca vitripennis</i> adult counts in 2010 and 2011.

<p>The raw data is shown as open circles, the means as solid circles. Species with counts of zero are not shown.</p

Life history responses of <i>H. vitripennis</i> to Australian native plants (combined 2010 and 2011 data).

<p>The instar figures are the proportion of nymphs that died at each instar stage out of 36; the remainder either survived or were eaten by ants. n is the total number of nymphs for which there was a record of date of death or total number of adults.</p>#<p><i>Banksia ericifolia×B. spinulosa</i>.</p

Percentage of egg masses parasitised and proportional parasitism for each species with s.e., lower and upper 95% confidence intervals (C.I) for 2010 and 2011 showing the total number of leaves with egg masses present (n).

<p>Proportion = number of parasitoids to number of H. vitripennis nymphs.</p>#<p><i>Banksia ericifolia×B. spinulosa</i>.</p

<i>Homalodisca vitripennis</i> incidence on Australian native plants in a field survey in California, USA from June–November (n = 9).

<p>Species back transformed means in each column assigned the same letter are not significantly different; citrus control with mean and standard error (n = 10) also provided.</p>∧<p>Citrus plants were not part of the randomised design and data not included in the ANOVA and not transformed.</p>†<p>Species effect not detected at p = 0.05.</p>#<p><i>Banksia ericifolia×B. spinulosa</i>.</p

Effect of Australian native plant species on feeding rate (excreta volume) and predicted survival proportion for 2010 and 2011 for <i>Homalodisca vitripennis</i> in a no choice feeding experiment over 72 hours.

<p>Species back transformed means in each column assigned the same letter are not significantly different.</p>#<p><i>Banksia ericifolia×B. spinulosa</i>.</p

<i>Homalodisca vitripennis</i> host status of Australian native plants in the field.

#<p><i>Banksia ericifolia×B. spinulosa</i>.</p