Feeding behaviour of the Asiatic citrus psyllid, Diaphorina citri, on healthy and huanglongbing‐infected citrus

Abstract

Diaphorina citri Kuwayama (Hemiptera: Sternorrhyncha: Psyllidae) is a vector of huanglongbing, a disease of citrus that in Asia is caused by ‘Candidatus Liberibacter asiaticus’ (α‐Proteobacteria) (Las). Acquisition of Las by D. citri appears to be variable, and this variability may be due to the suitability of the host plants and their tissues for acquisition. Therefore, this study aimed to determine the effect of symptom severity of the disease on the feeding behaviour of D. citri. Use of an electrical penetration graph showed that the pathway phase of D. citri consisted of four waveforms, A, B, C, and D; waveforms A and B have not been reported for D. citri before. The remaining waveforms, E1, E2, and G, conform to those described before for D. citri. The duration of the non‐penetration period did not differ between healthy or infected plants. However, in moderately and severely symptomatic plants, the duration of the pathway phase increased, whereas the phloem phase was shorter. In all diseased plants, the times to first and sustained salivation in the phloem were longer than those in control plants, with the times being related to symptom severity. As symptom expression increased, the percentage of time spent by psyllids salivating during the phloem phase increased; however, the percentage of time spent in phloem activities reduced gradually from ca. 74% in the control plants to ca. 8% in the severely symptomatic plants. In contrast, the percentage of time spent on xylem activities increased, as did the proportion of psyllids feeding from xylem. The differences in the durations of the E waveforms on plants showing different levels of symptom expression may account for differences in acquisition found amongst studies; therefore, future work on the acquisition and transmission of Las needs to carefully document symptom expression.

Stylet Morphometrics and Citrus Leaf Vein Structure in Relation to Feeding Behavior of the Asian Citrus Psyllid Diaphorina citri, Vector of Citrus Huanglongbing Bacterium

“…The piercing-sucking mouth parts of ACP adults and their salivary sheaths have been studied [16], [17], but those of nymphs have not been studied so far. Also, the feeding behavior of ACP adults, but not nymphs, has been studied with electrical penetration graphs (EPG) [16], [18]. ACP adults were found to ingest sap mainly from the phloem sieve elements, although occasionally they also appear to ingest sap from xylem vessels [16], [18].…”

Transmission of ‘Candidatus Liberibacter solanacearum’ by Bactericera trigonica Hodkinson to vegetable hosts

“…These components provide information on stylet tip position in specific plant tissues, time spent at each location, and stylet activity (Tjallingii, 1985). The EPG waveforms of psyllids are reported for D. citri (Bonani et al, 2010;Cen et al, 2012b), B. cockerelli (Butler et al, 2012;Pearson et al, 2014;Sandanayaka et al, 2014;Mustafa et al, 2015), C. pyri L. (Civolani et al, 2011) and Psylla pyricola Förster (Ullman & McLean, 1988). Comparison by EPGs waveforms of the probing behaviours of males and females of B. trigonica in carrot has been recently reported (Antolínez et al, 2017a) and the characterization of the electrical penetration graphs (Antolínez et al, 2017b).…”

Differences in Selection Behaviors and Chemical Cues of adult Asian Citrus Psyllids, Diaphorina citri, on Healthy and Huanglongbing-Infected Young Shoots of Citrus Plants

“…For this reason, after the initial attraction to the odors produced by Las-infected young shoots, D. citri might move to uninfected ones. The leathered surfaces of Las-infected citrus plants was not found to have any effect on choice of host plants by Asian citrus psyllids, although psyllids spent more time on Las-infected plants because of the longer time needed to penetrate the parenchyma and reach the phloem (Cen et al, 2012). Inoue et al (2009) found that a large proportion (88%) of D. citri adults contained the bacterium (Las) after an access period of 24 h. The movement of D. citri adults infected with Las can facilitate the spread of the pathogen.…”