Use of Lycium by potato psyllid in the Pacific Northwest lessons from the desert Southwest

Authors: THINAKARAN, JENITA - University Of Idaho; Horton, David; Cooper, William - Rodney; KARASEV, ALEXANDER - University Of Idaho

Submitted to: American Journal of Potato Research
Publication Type: Proceedings
Publication Acceptance Date: 4/10/2018
Publication Date: 7/12/2018
Citation: Thinakaran, J., Horton, D.R., Cooper, W.R., Karasev, A. 2018. Use of Lycium by potato psyllid in the Pacific Northwest lessons from the desert Southwest. American Journal of Potato Research. 95:226.

Interpretive Summary: Potato psyllid, Bactericera cockerelli (Šulc), is a major pest of potato (Solanum tuberosum L.; Solanaceae), including as a vector of the bacterial pathogen ‘Candidatus Liberibacter solanacearum’ that causes zebra chip disease of potato. Non-crop solanaceous plants have been shown to play key roles in survival and reproductive build-up of potato psyllid throughout the psyllid’s range. We now show that potato psyllid in the Pacific Northwest occurs throughout the year on two introduced species of Lycium (also known as matrimony vine or Goji berry). Psyllids exhibited spring and autumn peaks in numbers separated by a large drop in numbers during summer. The summer drop in numbers is similar to what has been shown for psyllid populations on Lycium andersonii and other native species of Lycium in the desert regions of the southwestern U.S. Seasonal disappearance of psyllids from native Lycium spp. in the southern U.S. appears to be due to leaf drop in response to high temperatures and low soil moisture. We observed a similar phenomenon of summer quiescence and leaf drop in our study of non-native Lycium spp. These results suggest that phenology of non-native Lycium and effects of phenology on potato psyllid in the Pacific Northwest are similar to what occurs in southern regions on native Lycium. Observations of native Lycium spp. from the southern U.S. may therefore be helpful in understanding aspects of psyllid ecology in the Pacific Northwest. Disappearance of psyllids from Lycium spp. during summer coincided with emergence of the potato crop and arrival of psyllids in potato fields, suggesting that Lycium could be a source of potato psyllids arriving in potato fields of the Pacific Northwest. Field trials to examine this hypothesis are ongoing.

Technical Abstract: Potato psyllid, Bactericera cockerelli (Šulc), is a major pest of potato (Solanum tuberosum L.; Solanaceae), including as a vector of the bacterial pathogen ‘Candidatus Liberibacter solanacearum’ that causes zebra chip disease of potato. Non-crop solanaceous plants have been shown to play key roles in survival and reproductive build-up of potato psyllid throughout the psyllid’s range. We now show that potato psyllid in the Pacific Northwest occurs throughout the year on two introduced species of Lycium (also known as matrimony vine or Goji berry). Psyllids exhibited spring and autumn peaks in numbers separated by a large drop in numbers during summer. The summer drop in numbers is similar to what has been shown for psyllid populations on Lycium andersonii and other native species of Lycium in the desert regions of the southwestern U.S. Seasonal disappearance of psyllids from native Lycium spp. in the southern U.S. appears to be due to leaf drop in response to high temperatures and low soil moisture. We observed a similar phenomenon of summer quiescence and leaf drop in our study of non-native Lycium spp. These results suggest that phenology of non-native Lycium and effects of phenology on potato psyllid in the Pacific Northwest are similar to what occurs in southern regions on native Lycium. Observations of native Lycium spp. from the southern U.S. may therefore be helpful in understanding aspects of psyllid ecology in the Pacific Northwest. Disappearance of psyllids from Lycium spp. during summer coincided with emergence of the potato crop and arrival of psyllids in potato fields, suggesting that Lycium could be a source of potato psyllids arriving in potato fields of the Pacific Northwest. Field trials to examine this hypothesis are ongoing.