|MUSTAFA, TARIQ - Washington State University|
|ALVAREZ, J - Dupont Crop Protection|
|Munyaneza, Joseph - Joe|
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/9/2015
Publication Date: N/A
Interpretive Summary: Zebra chip, a new and economically important disease of potato in the United States and several other countries, is caused by the bacterium Liberibacter vectored by the potato psyllid. Researchers at USDA-ARS Wapato in Washington, in collaboration with scientists at DuPont Crop Protection Company in Delaware, assessed the use of selected insecticides to prevent zebra chip transmission by its insect vector. It was determined that these insecticides were effective at deterring feeding behavior of potato psyllid and preventing transmission of the zebra chip pathogen by this insect pest. Information from this research will help potato growers effectively manage potato psyllid with the identified insecticides and reduce transmission and spread of zebra chip.
Technical Abstract: Zebra Chip (ZC) is a new and economically important disease of potato in the United States, Mexico, Central America, and New Zealand. ZC is caused by the phloem-limited bacterium “Candidatus Liberibacter solanacearum” (Lso) transmitted to potato by the potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae). Currently, use of insecticide applications targeted against the potato psyllid are the only means to manage ZC. However, potato psyllid ability to rapidly transmit Lso once it reaches the phloem tissue represents a substantial challenge for growers in controlling this insect vector and preventing ZC transmission. Cyantraniliprole, a novel second generation anthranilic diamide insecticide affecting ryanodine receptors in insect muscles, has been proved to deter insect feeding and oviposition, and reduce disease transmissions in other hemipteran vectors. In the current study, the affect of cyantraniliprole (Exirel) on potato psyllid probing behavior was assessed using the electrical penetration graph technique and compared with abamectin, an insecticide commonly used against this pest. Results showed that cynatraniliprole significantly deterred probing behavior of potato psyllid. Average duration of intracellular stylet penetration pathway on cyantraniliprole and abamectin-treated and untreated control plants was 2.59, 0.96, and 9.14 h, respectively. It took psyllids about 1.82, 1.20, 1.73 h to reach the xylem tissue of cyantraniliprole and abamectin-treated and untreated control plants, respectively. Xylem sap ingestion duration averaged 0.53, 1.07, and 4.58 h on cyantraniliprole and abamectin-treated and untreated controls, respectively. None of the psyllids exposed to insecticide-treated plants made it into the phloem tissue, except one that bypassed the xylem. The insects completely ceased probing 4.44 and 3.10 h on cyantraniliprole and abamectin-treated plants from the start of the EPG recordings, in contrast to those on untreated control plants that probed throughout the entire 24-h experiment duration. These results indicate that cyantraniliprole could help potato growers effectively manage potato psyllid and potentially reduce transmission of Lso and ZC spread.