Phenology of the Potato Psyllid, Bactericera cockerelli (Hemiptera: Triozidae), and “Candidatus Liberibacter solanacearum” in Commercial Potato Fields in Idaho

Abstract

Zebra chip disease (ZC) is an emerging disease of potato in which tubers are produced with striped necrotic patterns that make them unmarketable. ZC is associated with the bacterium "Candidatus Liberibacter solanacearum" (Lso), which is transmitted by the potato psyllid, Bactericera cockerelli (Šulc; Hemiptera: Triozidae). First found in Idaho during 2011, ZC now contributes to increased production costs each season via additional insecticide sprays. To clarify the extent and severity of the threat of ZC in Idaho, we sampled potato psyllids in commercial potato fields across the state over four growing seasons (2012-2015). All life stages of psyllids were sampled using a combination of methods (yellow sticky traps, vacuum samples, and leaf samples), and adult psyllids were tested for the presence of Lso by Polymerase Chain Reaction (PCR). Abundance of potato psyllids initially increased gradually over each growing season, then exhibited a sharp late-season rise and a sharp decline as most fields were being harvested. Abundance of psyllids was higher at warmer, lower elevation sites, but infestation onset did not differ between growing regions. Fewer psyllids were collected in vacuum samples than in sticky trap samples. Nymphs and eggs were found only late season and during years with high abundance of adults. Overall incidence of Lso was similar among all years but one. The results presented here clarify our understanding of the seasonal phenology of potato psyllids and Lso in Idaho potato fields and will aid in developing integrated management strategies against this important pest of potato.

Effects of Potato Psyllid Vector Density and Time of Infection on Zebra Chip Disease Development after Harvest and during Storage

“…Means within a column followed by the same letter are not significantly different based on pairwise comparisons and 95% confidence levels abundance typically is very low early during the season, increasing considerably around the time of harvest (Munyaneza et al 2009;Rondon 2012;Wenninger et al 2017). Similar phenologies have been reported in Texas (Goolsby et al 2007;Workneh et al 2014) and New Zealand (Cameron et al 2009).…”

“…Plants were replaced as needed. The presence of Lso in potato psyllids was determined by Polymerase Chain Reaction (PCR) using methods described by Wenninger et al (2017). The Lso status of the colonies was regularly tested and typically ranged from 80 to 100%.…”

“…Lso is transmitted by the potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae) (Hansen et al 2008;Liefting et al 2008;Munyaneza et al 2007aMunyaneza et al , 2007bSengoda et al 2010). Monitoring efforts in Idaho (Wenninger et al 2017), Washington (Munyaneza et al 2009), and Oregon (Rondon 2012) show that potato psyllids occur at relatively low levels during much of the year, but may increase considerably toward the end of the potato growing season. This increase mainly occurs as much of the crop is being vine killed or otherwise close to being harvested.…”

Seasonal Occurrence of Potato Psyllid (Bactericera Cockerelli) and Risk of Zebra Chip Pathogen (Candidatus Liberibacter Solanacearum) in Northwestern New Mexico

“…The presence of Lso in B. cockerelli was determined by Polymerase Chain Reaction (PCR). The details of the analysis are presented in Munyaneza et al [4], Wenninger et al [21], Workneh et al [17], and Harrison et al [28]. The percentage of adult B. cockerelli testing positive for Lso was determined as the ratio of the number of B. cockerelli positive for Lso to the total number of collected B. cockerelli during each week of the monitoring period of each year.…”

“…The results of the present study corroborate with the finding of Antolínez et al [33] who reported the arrival of potato psyllid in the potato fields when the average air temperature is greater than 15 • C and the peak population occurred when air temperature was about 25 • C in Spain. Wenninger et al [21] also correlated the population abundance of adults B. cockerelli with the accumulated thermal unit and found the population peak at 1775 • C in late August in the Treasure Valley and at 1498 • C in the Magic Valley in Idaho. Lewis et al [34] suggested integrating accumulated thermal units into the management and control of B. cockerelli and proposed a model that integrates thermal unit to simulate the development of potato psyllid infestation.…”