Analysis of historical and current distribution of potato psyllid (Bactericera cockerelli) and the induced plant disease psyllid yellows, in relation to standard climate indices

Abstract

The biogeography of herbivorous insects often depends on climate and host plants. Potato psyllid, Bactericera cockerelli (Sulc), is an insect that presents a threat to the western Canadian potato industry. It is native to the USA and Central America, and currently found at very low numbers on the Canadian Prairies. Potato psyllid can transmit Candidatus Liberibacter solanacearum (Lso), causing “zebra chip”, severe tuber necrosis. Feeding by potato psyllid nymphs causes psyllid yellows on potato leaves. Historical records of this disease indicate potato psyllid abundance. I used Random Forest model methods to analyze the climate conditions of the historical psyllid yellows records. I used Maxent models to predict the presence probability of potato psyllids. The results indicate that higher temperatures and moderate precipitation are related to larger potato psyllid populations, and suggest the northern expansion of climatically suitable range in western Canada and decrease in the southwestern USA under climate change.