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United States Department of Agriculture

Agricultural Research Service

Research Project: EPIDEMIOLOGY AND MANAGEMENT OF XYLELLA FASTIDIOSA (XF) AND OTHER EXOTIC AND INVASIVE DISEASES AND INSECT PESTS

Location: Crop Diseases, Pests and Genetics

Title: Characterization of EPG waveforms for the tea green leafhopper, Empoasca vitis Göthe (Hemiptera: Cicadellidae), on tea plants and their correlation with stylet activities

Authors
item Jin, Shan -
item Chen, Zong-Mao -
item BACKUS, ELAINE
item Sun, Xiao -
item Xiao, Bin -

Submitted to: Journal of Insect Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 19, 2012
Publication Date: September 1, 2012
Citation: Jin, S., Chen, Z., Backus, E.A., Sun, X.L., Xiao, B. 2012. Characterization of EPG waveforms for the tea green leafhopper, Empoasca vitis Göthe (Hemiptera: Cicadellidae), on tea plants and their correlation with stylet activities. Journal of Insect Physiology. 58:1235-1244.

Interpretive Summary: The tea green leafhopper, Empoasca vitis, causes hopperburn of tea plants throughout Asia and grapevines in Europe. Hopperburn symptoms include chlorosis and marginal leaf curling, followed by browning, shriveling, and necrosis that ultimately engulfs the leaves from outer edge to inside, followed by premature leaf drop. In extreme cases, damaged plants cease to grow and entire plants may die. Development of resistant varieties of tea and grape is underway; however efforts are presently hampered by lack of knowledge of how E. vitis feeding causes hopperburn. Feeding of E. vitis was studied using the DC electrical penetration graph (EPG) technique. Seven different EPG waveforms were identified and characterized on susceptible tea leaves. Four waveforms (Np, E1, E2, E3), accounting for 97.08% of the total recording time, were correlated with probing and non-probing activities based on high-magnification video recording of feeding on artificial diets. Active stylet movements and channel-cutting observed during probing indicate that E. vitis uses a cell rupture feeding strategy that is different from the salivary sheath strategy used by aphids and other leafhoppers. Thus, hopperburn damage to tea plants is probably due to cell rupture, similar to other hopperburning Empoasca species. Such benchmark information will allow future use of EPG for development of hopperburn-resistant varieties of tea.

Technical Abstract: Stylet probing activities of the tea green leafhopper, Empoasca vitis Göthe (Hemiptera: Cicadellidae), were studied using the DC electrical penetration graph (EPG) technique. Seven different EPG waveforms (i.e., Np, E1, E2, E3, E4, E5 and E6) were identified and characterized on susceptible tea leaves. Four waveforms (i.e., Np, E1, E2, E3) accounted for 97.08% of the total recording time and were correlated with probing and non-probing activities as observed by high-magnification video recording of feeding on artificial diets. At the start of stylet probing, waveform E1 always occurred at a variable voltage level. E1, including all three waveform sub-types (E1-A to E1-C), was associated with production of the salivary sheath trunk, stylet laceration, and channel cutting in viscous artificial diet. Two types of high-amplitude waveforms, E2 and E3, followed E1. E2 had a highly regular, quasi-square wave, repetitive appearance, and was recorded for the longest average duration per insect of all E. vitis waveforms. E3 usually appeared after E2, and also exhibited a quasi-square wave feature similar to E2, but had much higher amplitude. Waveforms E2 and E3 were correlated with active ingestion of liquid artificial diet. In addition, secretion of watery, enzymatic saliva was likely during E2. Active stylet movements and channel-cutting observed during the probing process indicate that E. vitis is cell rupture feeder, not a salivary sheath feeder as are aphids and most other leafhoppers. Thus, hopperburn damage to tea plants is probably due to the cell rupture feeding strategy, similar to other hopperburning Empoasca species. Because E. vitis is a severe pest on tea in Asia and grapevine in Europe, such benchmark information will allow future use of EPG for development of hopperburn-resistant varieties of these crops.

Last Modified: 8/19/2014
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