Determination of Cucumber Mosaic Virus Titer in Muskmelon by Enzyme-linked Immunosorbent Assay and Correlation with Aphid Transmission. M. T. Banik, Former Graduate Research Assistant, Department of Plant Pathology, Cornell University, Ithaca, NY 14853. T. A. Zitter, Associate Professor, Department of Plant Pathology, Cornell University, Ithaca, NY 14853. Plant Dis. 74:857-859. Accepted for publication 5 June 1990. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0857.

Percentage transmission by individual Aphis gossypii and spectrophotometric readings in indirect enzyme-linked immunosorbent assay (ELISA) were used to estimate cucumber mosaic virus (CMV) titers in muskmelon plants over a 7-wk period. Results indicated a high correlation between the two techniques with two distinct CMV isolates. One week after inoculation, the frequency of aphid transmission of CMV-243 (virulent isolate) was significantly higher than that of CMV-241 (mild isolate), and ELISA absorbance readings at 405 nm were significantly higher for isolate CMV-243. The apparent rapid increase of CMV-243 titer 1 wk after infection could provide one explanation for the difference in spread of the two CMV isolates observed in the field. Similar tests were conducted weekly, comparing mixed infections of CMV-243 and watermelon mosaic virus strain 2 (WMV-2) to single infections of each virus. There was no apparent difference in levels of aphid transmission or ELISA values from plants infected with the viruses singly or with mixed infections.