|LIN, PO-AN - Taiwan Agricultural Research Institute|
|CHANG, CHUNG-JAN - National Chung-Hsing University|
|SHIH, HSIEN-TZUNG - Taiwan Agricultural Research Institute|
Submitted to: Formosan Entomologist
Publication Type: Literature Review
Publication Acceptance Date: 12/16/2015
Publication Date: 10/27/2016
Citation: Backus, E.A., Lin, P., Chang, C., Shih, H. 2016. AC-DC electropenetrography: a new diagnostic technology for study of feeding behavior of piercing-sucking insects. Formosan Entomologist. 65:219-237.
Interpretive Summary: Many devastating agricultural pests in the world are hemipteran insects that transmit lethal plant pathogens, such as Asian citrus psyllids transmitting the citrus greening bacterium, or green peach aphids transmitting Potato virus Y. Other hemipterans, such as lygus bugs, cause direct feeding damage to crops via enzymatic saliva. Developing novel, non-pesticidal tactics to manage hemipteran pests is facilitated by studying insect feeding behaviors that result in transmission or direct damage. However, studying feeding of hemipterans is challenging because piercing-sucking mouthparts cannot be directly observed while being probed into opaque plant tissues. This challenge was overcome by the invention of electropenetrography, or electrical penetration graph (EPG) monitoring, which produces measurable electrical waveforms as a representation of feeding behaviors. Today, EPG is used for development of novel integrated pest management (IPM) tactics for hemipteran pests. This paper reviews: 1) principles and history of EPG, especially development of the new, third-generation AC-DC monitor, 2) what types of information can be gained via EPG, using aphids as a model system, and 3) how EPG can be applied to the special needs of Taiwanese agriculture, including seven aphid species of economic significance in Taiwan. Through collaboration with ARS scientists in Parlier, California, third-generation EPG technology is being established in Taiwan to improve development of non-pesticidal approaches to aphid control.
Technical Abstract: Studying feeding, plant damage, and transmission of plant pathogens by hemipteran insect pests is challenging. Hemipteran piercing-sucking mouthparts, the stylets, are probed into opaque plant tissues precluding direct observation. This challenge was overcome by the invention of electropenetrography, or electrical penetration graph (EPG) monitoring. Today, EPG is used in three main ways for development of novel integrated pest management (IPM) tactics for hemipteran pests. First, in cases where fundamental mechanisms of feeding damage or transmission of a plant pathogen are unknown, EPG is instrumental in identifying such mechanisms. Second, once feeding-related causes of damage or pathogen transmission are understood, EPG can be used to demonstrate effects of insecticides, antifeedants, or other chemical compounds on specific feeding behaviors responsible for damage or transmission. Third, EPG can similarly identify differential effects of resistant versus susceptible varieties of crop plants, including transgenic plants engineered to express biopesticides. The purpose of this paper is to review: 1) principles and history of EPG, especially development of the third-generation AC-DC monitor, 2) what waveforms and types of information can be gained via EPG, using aphids as a model system, and 3) how EPG can be applied to the study of seven aphid species of economic significance in Taiwan. This review combines information for all three types of EPG monitor for research on aphids, for the first time in print.