Responses of the Asian citrus psyllid to volatiles emitted by the flushing shoots of its rutaceous host plants

Authors: Patt, Joseph - Joe; SETAMOU, MAMOUDOU - Texas A&M University

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/12/2009
Publication Date: 4/8/2010
Citation: Patt, J.M., Setamou, M. 2010. Responses of the Asian citrus psyllid to volatiles emitted by the flushing shoots of its rutaceous host plants. Environmental Entomology. 39(2):618-624.

Interpretive Summary: The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), vectors the bacterial pathogens that causes citrus greening or Huanglongbing. ACP reproduces and develops only on the flushing shoots of its host plants, such as citrus trees and orange jasmine (Murraya paniculata (L.) Jack). Here we examined whether ACP is attracted to aroma volatiles emitted by the flushing shoots of several representative host plants. Tests conducted in a vertically-oriented Y-tube olfactometer showed that both males and females preferentially selected the Y-tube arm containing the odor from the shoots of Eureka lemon and orange jasmine. Only males exhibited a preference for the flush odor of sweet orange while the flush odor of Rio Red grapefruit was the least attractive to both sexes. The volatiles emitted by the flush of Rio Red grapefruit, Meyer lemon, and orange jasmine were analyzed by gas chromatography-mass spectrometery. The samples were comprised of monoterpenes, monoterpene esters, and sesquiterpenes. The number of compounds present varied from two to seventeen, while the total amount of sample collected over six hours ranged from 5.6 to 119.8 ng. The quantitatively dominant constituents were (E)-ß-ocimene, linalool, linalyl acetate, and ß-caryophyllene. The attractiveness of a mixture of synthetic terpenes, modeled on the volatiles from orange jasmine flush, was evaluated in screened cages in a no-choice test. At three observation intervals, significantly more individuals were trapped on white targets scented with the mixture than on unscented targets. These results indicate the feasibility of developing ACP attractants patterned on actual flush volatiles.

Technical Abstract: Diaphorina citri Kuwayama (Hemiptera: Psyllidae) vectors Candidatus Liberibacter spp., the putative causal agents of Huanglongbing. D. citri reproduces and develops only on the flushing shoots of its rutaceous host plants. Here we examined whether D. citri is attracted to volatiles emitted by the flushing shoots of several representative host plants. Tests conducted in a vertically-oriented Y-tube olfactometer showed that both males and females preferentially selected the Y-tube arm containing the odor from the shoots of orange jasmine (Murraya paniculata (L.) Jack) and Eureka lemon (Citrus limon (L.) Burm. f. cv Eureka). Only males exhibited a preference for the flush odor of sweet orange (C. sinensis L). while the flush odor of Rio Red grapefruit (C. × paradisi MacFadyen cv Rio Red) was the least attractive to both sexes. The volatiles emitted by the flush of Rio Red grapefruit, Meyer lemon (Citrus × limon L. Burm.f.), and orange jasmine were analyzed by gas chromatography-mass spectrometery. The samples were comprised of monoterpenes, monoterpene esters, and sesquiterpenes. The number of compounds present varied from two to seventeen, while the total amount of samples collected over six hours ranged from 5.6 to 119.8 ng. The quantitatively dominant constituents were (E)-ß-ocimene, linalool, linalyl acetate, and ß-caryophyllene. The attractiveness of a mixture of synthetic terpenes, modeled on the volatiles from orange flush, was evaluated in screened cages in a no-choice test. At three observation intervals, significantly more individuals were trapped on white targets scented with the mixture than on unscented targets. These results indicate the feasibility of developing D. citri attractants patterned on actual flush volatiles.