Evaluation of color and scent attractants used to trap and detect Asian citrus psyllid (Hemiptera:Liviidae) in urban environments

Authors: GODREY, KRISTINE - University Of California; GALINDO, CELASTINA - California Department Of Food And Agriculture; Patt, Joseph - Joe; LUQUE-WILLIAMS, MAGALLY - California Department Of Food And Agriculture

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/29/2013
Publication Date: 12/1/2013
Citation: Godrey, K.E., Galindo, C., Patt, J.M., Luque-Williams, M. 2013. Evaluation of color and scent attractants used to trap and detect Asian citrus psyllid (Hemiptera: Liviidae) in urban environments. Florida Entomologist. 96(4):1406-1416.

Interpretive Summary: Huanglongbing, a devastating disease of citrus, is spread by a tiny insect, the Asian citrus psyllid (abbreviated as ‘ACP’). ACP populations increase in urban areas and then move out into commercial citrus orchards. Current methods for detecting ACP in urban areas rely on the use of yellow sticky card traps. This method was selected because of its used in commercial production, however, in urban settings, it may not be the most efficient method for detecting ACP. We investigated the relative trapping efficiency of four different colored traps (2 hues of yellow and 2 hues of green) and the addition of two scent lures to yellow sticky traps. The lures were based on the aromas of the young shoots of Eureka lemon and Mexican lime. The tests were conducted in residential areas in Los Angeles, California, in 2011. There were no differences in trap catch between the yellow and green traps. The type of tree on which the traps were placed influenced trap catch, with traps on lemon and lime trees capturing more psyllids than traps placed on calamondin, kumquat, grapefruit, or tangerine trees. When scent lures were added to traps, the type of tree in which the traps were placed also had an influence on the results. For the lemon scented lure, more psyllids were captured on traps in lemon and grapefruit trees than on traps placed in orange trees. For the Mexican lime scented lure, more psyllids were captured on traps placed in orange trees than in lime and grapefruit trees. Tree type may affect trap catch because the aroma it produces may compete, interfere, or otherwise interact with the lure. Alternatively, the psyllids may be attracted to a lure scent that matches that of the host plant. Further refinement of the scent lures is necessary to improve the detection of Asian citrus psyllids in urban areas.

Technical Abstract: The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is a serious pest of citrus due to its ability to vector the putative causal agent of huanglongbing. Populations of Asian citrus psyllid (ACP) can increase in density in urban areas and then move out into adjacent commercial citrus production. Current presence/absence detection methods for ACP in urban areas rely on the use of yellow sticky traps without a scent lure. This method was selected because of its accepted use in commercial production, however, in urban settings, it may not be the most efficient method for detecting ACP. Therefore, we investigated the relative trapping efficiency of four different colored traps (2 hues of yellow and 2 hues of green) and the addition of two scent lures to yellow sticky traps. The lures were based on the volatiles emitted either from flush growth of Eureka lemon or Mexican lime. The tests were conducted in residential areas in Los Angeles, California, in 2011. There were no statistically significant differences in trap catch between the yellow and green traps. The host plant on which the colored traps were placed influenced trap catch with traps on lemon and lime trees capturing more psyllids than traps placed on calamondin, kumquat, grapefruit, or tangerine trees, regardless of trap color. When scent lures were added to yellow sticky traps, the host plant effect was also apparent. For the Eureka lemon scent lure, more psyllids were captured on traps with lure placed on lemon and grapefruit trees than on traps with lure placed on orange trees. For the Mexican lime scent lure, more psyllids were captured on traps with lure placed on orange trees than on traps with lure placed on lime and grapefruit trees. The lime trees with traps with lure had more flush present than the lime trees with traps without lures, and this may have contributed to the lower trap catches. The host plant may affect trap catch because the volatiles it produces may compete, interfere, or otherwise interact with the lure. Alternatively, the psyllids may be attracted to a lure scent that matches that of the host plant. Further refinement of the scent lures is necessary to improve the detection of Asian citrus psyllids in urban areas.