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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Crop Diseases, Pests and Genetics Research » Research » Publications at this Location » Publication #204548
Title: The AC-DC correlation monitor: New EPG design with flexible input resistors to detect both R and emf components for any piercing-sucking hemipteran

Author
item Backus, Elaine
item BENNETT, WILLIAM - SELF-EMPLOYED

Submitted to: Journal of Insect Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/19/2009
Publication Date: 6/10/2009
Citation: Backus, E.A., Bennett, W.H. 2009. The AC-DC correlation monitor: New EPG design with flexible input resistors to detect both R and emf components for any piercing-sucking hemipteran. Journal of Insect Physiology. 55:869-884.

Interpretive Summary: Much of what is known today about the feeding biology of piercing-sucking insects of plants has been revealed by use of electrical penetration graph (EPG) technology, or electronic monitoring of insect feeding. Key to all of this information has been the electronic designs of EPG monitors. Herein we describe the development of a new AC-DC Correlation Monitor, a major improvement in monitor design since the DC monitor. We provide the monitor’s block diagram and circuit description, and discuss its application to aphid feeding. The instrument combines design features from the existing AC and DC monitors, plus several new innovations. This research demonstrates that AC electronics can duplicate the level of detail of aphid waveforms previously provided only by the DC monitor. The instrument is a single, flexible, universal monitor that can be used to provide maximum detail on feeding for any piercing-sucking species. This will allow research on DC-sensitive, non-aphid piercing-sucking pests, such as the glassy-winged sharpshooter, providing the same level of detail as is now routine for aphids. The enhanced information will aid in development of host plant resistance, simulation modeling of disease spread, and integrated pest management.

Technical Abstract: Much of what is known today about hemipteran feeding biology, as well as mechanisms of their host plant interactions and transmission of phytopathogens, has been revealed by use of electrical penetration graph (EPG) technology, or electronic monitoring of insect feeding. Key to all of this information has been the electronic designs of EPG monitors. It has been 43 years since the development of the original EPG, the AC monitor, and 29 years since introduction of the DC monitor, an important improvement for aphid studies. Herein we announce the development of our new AC-DC Correlation Monitor, the first major improvement in design since the DC monitor. We provide the monitor’s block diagram and circuit description, and discuss its application to aphid feeding waveforms. Our instrument combines design features from the existing AC Missouri Monitor and the DC Tjallingii monitor, plus several new innovations. It can produce three simultaneous, parallel, time-synchronized, output signals from a single insect, via either AC or DC signal processing circuitry, as well as using either AC, DC, or AC-plus-DC substrate voltage. Our research conclusively demonstrates that AC signal processing can duplicate the level of detail and fidelity of aphid waveforms previously provided only by the DC monitor, including all R and emf component waveforms. We also determined the subtle reasons why published waveforms from older AC- and DC-monitors appeared to differ so much. Our instrument is a single, flexible, universal system that can be used to provide maximum, R-plus-emf waveform information from any piercing-sucking species.