|RODDEE, JARIYA - Suranaree University|
|WANGKAREE, J - Thammasat University|
|HANGOONSONG, YUPA - Khon Kaen University|
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/4/2021
Publication Date: 4/3/2021
Citation: Roddee, J., Backus, E.A., Wangkaree, J., Hangoonsong, Y. 2021. Alteration in the stylet probing behavior and host preference of the vector Matsumuratettix hiroglyphicus (Hemiptera:Cicadellidae) after infection with Sugarcane White Leaf Phytoplasma. Journal of Economic Entomology. 114(3):1081-1090. https://doi.org/10.1093/jee/toab059.
Interpretive Summary: Phytoplasmas are potent, damaging plant pathogens reported to attack at least 99 plant species. Sugarcane white leaf (SCWL) disease is caused by an as-yet unnamed plant pathogenic phytoplasma that results in loss of cane yield. SCWL is the most economically important disease of sugarcane in Thailand, and one of the most severe in Southeast Asia, causing economic hardship because the sugarcane industry employs more than 1.5 million people and generates about US$6 billion per year for the Thai economy. The leafhopper Matsumuratettix hiroglyphicus is a crucial insect carrier of the SCWL phytoplasma. The aim of this study was to compare the feeding behaviors of M. hiroglyphicus on healthy sugarcane plants, asymptomatic, and symptomatic SCWL-infected sugarcane plants, using DC electropenetrography. Mean durations per insect of both phloem ingestion (the phytoplasma- acquisition behavior) and phloem salivation (the phytoplasma-inoculation behavior) were significantly longer on both types of infected sugarcane than on healthy plants. Thus, phytoplasma infection somehow stimulates the leafhopper vector to perform the behavior that will cause a higher amount of phytoplasma acquisition, aiding the spread of the phytoplasma. Our study thus contributes to a better understanding of the interactions between the insect carrier and SCWL phytoplasma-infected plants and will aid in developing novel disease management tactics for sugarcane.
Technical Abstract: The leafhopper Matsumuratettix hiroglyphicus (Matsumura) (Hemiptera: Cicadellidae) is a crucial insect vector of the phytoplasma associated with sugarcane white leaf (SCWL) disease. The aim of this study was to compare the stylet probing behaviors of M. hiroglyphicus on healthy sugarcane plants, asymptomatic, and symptomatic SCWL-infected sugarcane plants, using DC electropenetrography. We also used host-selection preference (free-choice) assays to identify the preferred types of host plants, and scanning electron microscopy to observe stylet puncture holes and salivary flanges after leafhopper probing. According to a quantitative analysis of M. hiroglyphicus stylet probing, mean durations per insect of both phloem ingestion (waveform D; the phytoplasma-acquisition behavior) and phloem salivation (waveform C; the phytoplasma-inoculation behavior) were significantly longer on both types of infected sugarcane than on healthy plants. These longer overall durations were mainly because the same number of significantly longer-duration C and D events were performed on infected sugarcane compared with healthy plants. On free-choice tested plants, M. hiroglyphicus displayed a significantly greater preference to settle on the infected plants (both types) than the healthy sugarcane. These results provide the first empirical evidence that acquiring the SCWL phytoplasma alters the host-selection and stylet probing behaviors of its main vector, M. hiroglyphicus. Our study thus contributes to a better understanding of the interactions between the insect vector and SCWL phytoplasma-infected plants and will aid in developing novel disease management tactics for sugarcane.