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
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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.
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