Theses and Dissertations Collection

Zebra chip disease (ZC) in potato is associated with “Candidatus Liberibacter

solanacearum” (Lso), which is transmitted by the potato psyllid Bactericera cockerelli

(Šulc) (Hemiptera: Triozidae). Zebra Chip can cause large economic losses when disease

incidence is high. ZC management is currently focused on managing populations of the

psyllid vector with insecticides. Host plant resistance to Lso and ZC has been

investigated, but no commercial potato variety has been found resistant to the pathogen

or the disease symptoms. Three Lso-resistant breeding clones with reduced ZC

symptoms have been derived from a potato relative Solanum chacoense Bitter. Our

study was designed to screen these genotypes for their effects on the psyllid’s host

acceptance behavior and fecundity. The breeding clones selected were: ‘A07781-10LB’

(‘10LB’), ‘A07781-3LB’ (‘3LB’) and ‘A07781-4LB’ (‘4LB’). ‘Russet Burbank’ (Solanum

tuberosum L.) was used as a Lso-susceptible control. We conducted no-choice assays

with intact potato leaflets and observed the following behaviors: probing, walking,

cleaning and leaving the leaf. We also compared oviposition and egg fertility for psyllids

held on these genotypes. Probing frequency and female walking duration were highest

on Russet Burbank, suggesting greater activity on Russet Burbank than on the three

resistant genotypes. Fecundity did not differ among genotypes but declined on all

genotypes during the last period of observation (18-20 days after pairing with a male).

Egg fertility did not differ among genotypes for the first three observation periods

(16-18 days after pairing with a male) but was higher on Russet Burbank than 10LB or

3LB during the last observation period (18-20 days after pairing with a male). For

these genotypes with putative resistance to Lso, we found antibiotic effects on egg

fertility. Our study found little to no evidence of antixenotic or antibiotic effects on

psyllid settling behavior.