Discrimination among host plants (Leucaena species and accessions) by the psyllid pest Heteropsylla cubana and implications for understanding resistance

Abstract

1 The herbivorous bug Heteropsylla cubana Crawford (Homoptera: Psyllidae) is a pest of the cattle fodder crop Leucaena (Leguminosae: Mimosoideae). The interaction between the psyllid and three varieties of its Leucaena host plant was investigated in relation to the apparent resistance of some Leucaena varieties (Leucaena leucocephala, Leucaena pallida and their hybrids) to attack.2 Field trials demonstrated that adult psyllids distinguished among the different varieties of Leucaena over a distance, and were attracted to L. leucocephala in significantly higher numbers than to L. pallida or to the hybrid. Pesticide treatment increased the attractiveness of Leucaena plants, even of those deemed to be psyllid resistant. Numbers of psyllid eggs and nymphs, sampled in the field, reflect the arrival rates of adults at the three plant varieties. 3 Wavelength reflectance data of the three Leucaena varieties were not significantly different from one another, suggesting that psyllids cannot discriminate among the three plants using brightness or wavelength cues. There was a differential release of caryophyllene among the three varieties. Release of caryophyllene in L. leucocephala and the hybrid appeared to be influenced by environmental conditions. 4 Experiments demonstrated that caryophyllene (at least on its own) did not influence the behaviour of leucaena psyllids in relation to leucaena plants. 5 The results suggest that host plant volatiles cannot be dismissed as significant in the interaction between the leucaena psyllid and its Leucaena host plants.Further avenues for investigation are recommended and these are related to novel ways of understanding resistance in insect plant inter-relationships.

Electrophysiological responses of the blue willow leaf beetle, Phratora vulgatissima, to volatiles of different Salix viminalis genotypes

“…Its emission is known to be enhanced after insect feeding in several plants (Wegener et al, 2001;Blackmer et al, 2004;Colazza et al, 2004;Finlay-Doney & Walter, 2005;Szafranek et al, 2005). Its emission is known to be enhanced after insect feeding in several plants (Wegener et al, 2001;Blackmer et al, 2004;Colazza et al, 2004;Finlay-Doney & Walter, 2005;Szafranek et al, 2005).…”

Multimodal Cues Drive Host-Plant Assessment in Asian Citrus Psyllid (Diaphorina citri)

“…A number of psyllid species (Moran and Brown 1973;Lapis and Borden 1993;Soroker et al 2004;Finley-Doney and Walter 2005;Kristoffersen et al 2008;Mayer et al 2008aMayer et al ,b, 2011 are responsive to olfactory cues emitted by their host-plants. Given the aromaticity of rutaceous plants, it is reasonable to expect that olfactory stimuli play an important role in D. citri host-plant Þnding behaviors, and indeed initial studies indicate this to be the case (Wenninger et al 2009, Patt andSé tamou 2010).…”

Waterlogging increases the infestation level of the pest psyllidCreiis lituratusonEucalyptus dunnii

“…Pre-alighting recognition by hostseeking gravid females is based on olfaction and vision cues at both the crown and leaf scales. Finlay-Doney and Walter (2005) proposed that the number of psyllid (Heterop.1ylla cubana) eggs present on Leucaena sp. (a legume crop) is a function ofpsyllid arrival rates on the plants rather than a direct reflection of the suitability of the substrate for nymphal performance.…”