Evaluation of Potato Psyllid, Bactericera Cockerelli (Sulc) (Hemiptera: Triozidae), Host Preferences, Adaptation, Behavior, and Transmission of 'Candidatus Liberibacter Solanacearum' among Wild and Cultivated Solanaceous Hosts in the Lower Rio Grande Valley of Texas
Abstract
Host plant preferences of the potato psyllid B. cockerelli among wild and cultivated
solanaceous hosts in the Lower Rio Grande Valley of Texas, and transmission of the
endosymbiotic bacterial pathogen, ‘Candidatus Liberibacter solanacearum’ (Lso) were
evaluated. Settling and ovipositional behavior of B. cockerelli was studied to determine
preference for potato, tomato, pepper, eggplant and silverleaf nightshade (SLN) hosts.
Results of field testing indicate resident B. cockerelli preferred potato and tomato
equally for settling and oviposition, moving to pepper, eggplant and SLN only in the
absence of potato and tomato. However, under laboratory conditions B. cockerelli adults
preferred eggplant, pepper and potato equally, and more than tomato and SLN. Based on
psyllid abundance, B. cockerelli were more active during the morning and less active
during the afternoon. Preference for larger hosts in terms of size was exhibited,
irrespective of the host. Growth and survival of B. cockerelli was better on potato than
SLN. Lso-infectivity influenced nymphal survivorship and Lso-free individuals survived
better than Lso-infective on both potato and SLN. Contrary to our hypothesis and
published literature, psyllids preferred uninfected hosts and, in most cases, did not
exhibit any preference for Lso-infected or uninfected potato, tomato or pepper. Results
from field studies demonstrated that significantly more resident psyllids settled on
uninfected potato plants than Lso-infected plants. Although previous results indicate the
importance of olfactory cues to guide psyllid orientation to hosts, our results demonstrate
that psyllids more likely use visual cues, preferring healthy and vigorous instead of sick
and dying hosts. B. cockerelli acquired Lso from infected SLN, becoming infective within two weeks and transmitted Lso back to potato. It remains unclear if SLN retains Lso after exposure to temperatures routinely >35˚C. Findings from this study will lead to useful information that can be used in a attract-and-kill scenario by attracting B. cockerelli adults to preferred hosts that can be used as a trap crop near potato fields. Results further highlight mechanisms that psyllids adopt in making choices for preferred hosts and opens up avenues for establishing host preference study protocols.
Subject
Bactericera cockerelliLiberibacter
Potato psyllid
Settling
Host preferences
Life Tables
Silverleaf nightshade
Citation
Thinakaran, Jenita (2014). Evaluation of Potato Psyllid, Bactericera Cockerelli (Sulc) (Hemiptera: Triozidae), Host Preferences, Adaptation, Behavior, and Transmission of 'Candidatus Liberibacter Solanacearum' among Wild and Cultivated Solanaceous Hosts in the Lower Rio Grande Valley of Texas. Doctoral dissertation, Texas A & M University. Available electronically from https : / /hdl .handle .net /1969 .1 /152769.