Feeding Behavior of Asian Citrus Psyllid [Diaphorina citri (Hemiptera: Liviidae)] Nymphs and Adults on Common Weeds Occurring in Cultivated Citrus Described Using Electrical Penetration Graph Recordings

Abstract

Asian citrus psyllid, Diaphorina citri, transmits Candidatus Liberibacter asiaticus (CLas), the putative causal agent of Huanglongbing disease. Although they primarily feed on the phloem of Citrus and related plants, when grove or host conditions are unfavorable, D. citri may be able to use weed species as alternate food sources for survival. To explore this possibility, electrical penetration graph (EPG) recordings (18 h) were performed to investigate the feeding behavior of psyllid adults and nymphs on three common south Florida weeds (Bidens alba, Eupatorium capillifolium, and Ludwigia octovalvis). EPG recordings revealed that the proportion of time spent by D. citri feeding on xylem was similar on all tested weed species (19%–22%) and on the positive control (20%), the preferred host, Citrus macrophylla. Very little to no phloem feeding was observed on weed species by either nymphs or adults. Histological studies using epifluorescence microscopy showed that salivary sheaths were branched and extended into xylem of weed species, whereas they ended in phloem on citrus plants. No choice behavioral assays showed that adults can obtain some nutrition by feeding on weed species (xylem feeding) and they may be able to survive on them for short intervals, when host conditions are unfavorable.

Uncovering Symbionts Across the Psyllid Tree of Life and the Discovery of a New Liberibacter Species, “Candidatus” Liberibacter capsica

“…L. asiaticus, but it has been recorded as an alternative host for the vector, Diaphorina citri, in Florida (where HLB is now endemic), with evidence that it may also support D. citri reproduction (Thomas and De León, 2011). Use of Ficus by D. citri has not been explored extensively outside of this one study, but several other recent reports document use of various alternative hosts by D. citri adults, likely as a source of water (Zhang et al, 2019;George et al, 2020). These ecological studies of D. citri host use suggest there are pathways for rare Ca.…”

“…citri has not been explored extensively outside of this one study, but several other recent reports document use of various alternative hosts by D . citri adults, likely as a source of water ( Zhang et al, 2019 ; George et al, 2020 ). These ecological studies of D .…”

Adaptability and ‘CandidatusLiberibacter asiaticus’ titres of Diaphorina citri adults on three weed species in China

“…This study showed that D. citri survival was extended in the presence of weeds compared with starvation conditions with and without water, indicating that adults could obtain water as well as food resources from all the weed species tested in this paper in the absence of a host. By using electrical penetration graph (EPG) recordings, George et al 29 found that D. citri adults may be able to use some weed species opportunistically as secondary host plants for acquiring water or alternate food. However, the adaptabilities of D. citri to the three weed species differed to a certain extend.…”

Assessment of Variation in Feeding Behavior by Color Morph in the Asian citrus Psyllid (Diaphorina citri)

“…These results suggest that under the conditions in which most EPG experiments are performed (laboratory, with properly maintained colonies not under Although we did not detect differences in phloemrelated parameters among color morphs, we did detect a pattern of blue-green ACP morphs ingesting more xylem sap than the other two morphs. The xylem is nutrient poor relative to the phloem, but does provide moisture and some micronutrients (George et al 2020). If the pattern we observed is biologically relevant, it could indicate that blue-green morphs may have different requirements for managing water balance and may try to compensate for this by modulating xylem sap intake.…”

“…´Valencia.` Since blue-green morphs perform better in activities that have higher energy demands, such as dispersal and immune response (Martini et al 2014;Hosseinzadeh et al 2021), we hypothesized that there would be more efficient and/or prolonged nutrient uptake bouts from phloem tissue by blue-green ACP relative to the other two color morphs. Psyllids feed from both xylem and phloem tissues, but use phloem sap as a primary source of nutrients (Hodkinson 1974;Antolinez et al 2017;Ebert et al 2018;George et al 2020) linking phloem directly to the psyllid energy demands. Phloem access and exploitation is also essential for CLas transmission.…”