The fate of maize chlorotic dwarf virus (MCDV) in the black-faced leafhopper, Graminella nigrifrons (Forbes) (Homoptera: Cicadellidae)

Abstract

Ultrathin sections of tissues, organs, and whole bodies of black-faced leafhoppers, Graminella nigrifrons (Forbes), were examined by transmission electron microscopy. Virions were observed adsorbed only to the intima of the sucking pump, pharynx, and esophagus of leafhoppers fed for 48 hours on maize chlorotic dwarf virus (MCDV) infected com plants. Groups of virions observed free in the lumen were apparently released from retention sites. No other indications of virions were found in the fore alimentary canal and no virions were observed posterior to the esophageal valve, in any body tissue, or on the surface of stylets or claws. No virion retention sites were found in the nonvector leafhopper, Dalbulus maidis (DeLong and Wolcott), fed for 48 hours on MCDV-infected com plants. Virions were not observed in control G. nigrifrons fed on healthy oats or com or fed on MCDV-infected com plants and then fed for 48 hours on healthy oats or com plants. These findings indicate that MCDV is transmitted in a manner consistent with the ingestion-egestion hypothesis of noncirculative transmission.