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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 and correlation of new EPG waveforms for the corn leafhopper Dalbulus maidis (Hemiptera: Cicadellidae)

Authors
item Carpane, Pablo -
item Wayadande, Astri -
item Backus, Elaine
item Dolezal, William -
item Fletcher, Jacqueline -

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 25, 2011
Publication Date: May 1, 2011
Citation: Carpane, P., Wayadande, A., Backus, E.A., Dolezal, W., Fletcher, J. 2011. Characterization and correlation of new EPG waveforms for the corn leafhopper Dalbulus maidis (Hemiptera: Cicadellidae). Annals of the Entomological Society of America. 104(3):515-525.

Interpretive Summary: Plant diseases are economically important problems for corn production. In the Americas, three phloem-restricted pathogens (corn stunt spiroplasma, maize bushy stunt phytoplasma, and maize rayado fino virus) are transmitted by the corn leafhopper, Dalbulus maidis. Host plant resistance would be the most effective means of disease management. However, development of resistance is hindered by lack of understanding of the mechanisms of acquisition and inoculation of these pathogens by insect vectors. Insect feeding plays an important role in this mechanism, and thus spread of pathogens. The specific objective of this work is to understand the different stylet penetration activities performed by this insect while it feeds on corn plants, with the long-term goal of identifying sources of resistance to the vector in corn. Using electrical penetration graph (EPG) technology, six distinct waveforms were identified and correlated with different stylet activities of D. maidis, by monitoring transmission of spiroplasma plant pathogens that live strictly in the phloem, as well as excretion of honeydew. This work provides basic information relevant to the understanding of stylet penetration behaviors of D. maidis and to the characterization of potential sources of insect-resistant corn.

Technical Abstract: Corn leafhopper, Dalbulus maidis, is a vector of three corn pathogens that have become limiting factors for corn production in some areas of the Americas. Insect feeding plays an important role in acquisition and inoculation of pathogens by their insect vectors, and thus spread of the pathogen. The specific objective of this work is to understand the different stylet penetration activities performed by this insect while it feeds on corn plants, with the long-term goal of identifying sources of resistance to the insect vector in corn. Using electrical penetration graph (EPG) technology, six distinct waveforms were characterized and correlated with different stylet activities of D. maidis by monitoring transmission of spiroplasmas and excretion of honeydew. Major waveforms defined correspond to stylet pathway (waveform 1), active ingestion from non-sieve elements (waveform 2), nonvascular probing (waveform 3), phloem contact (waveform 4), phloem sieve element ingestion (waveform 5), and oviposition (waveform 6). Results support previous findings with this species, and also indicate that some waveforms (2, 4 and 5) are caused by biopotentials generated during probing, as was previously found for other hemipteran species. This work provides basic information relevant to the understanding of stylet penetration behavior of D. maidis and to the characterization of potential sources of insect-resistant corn.

Last Modified: 7/22/2014
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