Leafhopper Transmission and Host Range of Maize Rayado Fino Virus

Publisher Website
Google Scholar
Abstract
The leafhoppers, Dalbulus maidis, D. elimatus, Stirellus bicolor and Graminella nigrifrons, transmitted a Texas [USA] isolate of maize rayado fino virus (MRFV) to 70.0, 25.0, 11.5 and 9.7% of test corn plants, respectively, when 10 insects/plant were used. In one test, groups of 5 Baldulus tripsaci transmitted MRFV to 2 of 6 test plants. The leafhopper, Macrosteles fascifrons; the aphid, Rhopalosiphum padi; and the planthopper, Peregrinus maidis did not transmit MRFV. In a comparative test the transmission rate by single D. maidis was 15.0% with a mean latent period of 16.0 days when leafhoppers acquired virus from plants, whereas the rate of transmission for leafhoppers injected with 10 .mu.g of partially purified virus was 77% with a mean latent period of 6.9 days. Transmission efficiencies of male (10.5%) and female (9.2%) leafhoppers were similar. First instar D. maidis nymphs acquired and transmitted virus more efficiently (13.5%) than did adults (3.5%). In tests during a period of 2.5 yr, 12.0% (0-20% range) of 1753 single D. maidis transmitted MRFV. When vector male and female leafhoppers were selected for breeding, 38.7% of 98 resultant sib 1 offspring transmitted MRFV. Of the 48 gramineous species or subspecies in 25 genera tested, only Zea mays and its teosinte subspecies, Z. luxurians, Z. diploperennis, Tripsacum australe, Rottboellia exaltata, and several Z. mays .times. T. dactyloides hybrids were susceptible to MRFV. The tropical weed, R. exaltata, could serve as an over-seasoning host for MRFV in the southern USA and Latin American countries. The absence of an overwintering host for MRFV may be the only factor preventing spread of MRFV to the USA corn belt, since an abundant vector, G. nigrifrons, is already present.