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

Asian citrus psyllid, , transmits Liberibacter asiaticus (Las), the putative causal agent of Huanglongbing disease. Although they primarily feed on the phloem of and related plants, when grove or host conditions are unfavorable, . 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 (, , and ). EPG recordings revealed that the proportion of time spent by feeding on xylem was similar on all tested weed species (19%-22%) and on the positive control (20%), the preferred host, . 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.