|Munyaneza, Joseph - Joe|
Submitted to: Journal of Economic Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/6/2013
Publication Date: 10/30/2013
Citation: Sengoda, V.G., Buchman, J.L., Henne, D.C., Pappu, H.R., Munyaneza, J.E. 2013. 'Candidatus Liberibacter solanacearum' titer over time in Bactericera cockerelli (Hemiptera: Triozidae) after acquisition from infected potato and tomato plants. Journal of Economic Entomology. 106(5):1964-1972. Interpretive Summary: Zebra chip, a new disease of potato, has caused millions of dollars in losses to the potato industry in the United States, Mexico, Central America, and New Zealand. The disease is caused by the bacterium Liberibacter transmitted to potato by the potato psyllid. Researchers at USDA-ARS Wapato, WA, Washington State University, and Texas A&M University assessed how fast this bacterium multiplies in its insect vector. It was discovered that it takes two weeks for the potato psyllids to become infective, following feeding on infected plants. This information will help researchers and potato producers reduce damage caused by zebra chip by timely and appropriately controlling the potato psyllid, the insect vectoring the plant pathogen.
Technical Abstract: The potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae) is a serious pest of potato and other solanaceous crops. Recently, B. cockerelli has been associated with the bacterium “Candidatus Liberibacter solanacearum” (Lso), the causal agent of zebra chip, a new and economically important disease of potato in the U.S., Mexico, Central America, and New Zealand. The biology of liberibacter transmission to potato and other host plants by the potato psyllid is largely unknown. The present study determined Lso acquisition by adult psyllids following different acquisition access periods (AAP) on potato and tomato, quantified Lso titer over time in post-acquisition psyllids, determined Lso-acquisition rate in psyllids at each AAP on each source of inoculum, and determined influence of host plant Lso titer on Lso acquisition rates and post-acquisition titers in psyllids over time. Results showed that Lso detection rates and titer increased over time in psyllids following AAPs of 8, 24 and 72 h on tomato and potato and Lso titer was highest when psyllids acquired Lso from tomato vs. potato. Lso titer ranged from 200 - 400-fold higher in tomato leaves, petioles, and stems than those of potato. The increase of Lso titer in the insects reached a plateau after an average of 15 d following 24 and 72 h AAP on potato or tomato. At this 15d-plateau, Lso titer in post-acquisition psyllids was comparable to that of infective psyllids from the Lso-infected laboratory colony. Lso-acquisition rate in psyllids fed on potato and tomato increased up to 5 and 20, 15 and 35, 35 and 75, and 80 and 100%, respectively, when the insects were allowed access to plants for 4, 8, 24, and 72 h, respectively.