MAIZE CHLOROTIC MOTTLE VIRUS IN HAWAIIAN-GROWN MAIZE - VECTOR RELATIONS, HOST RANGE AND ASSOCIATED VIRUSES

Studies were conducted on Kauai, Hawaii to identify potential above-ground arthropod vectors of maize chlorotic mottle virus (MCMV), to survey for plants serving as reservoirs for MCMV and also to survey for associated viruses in maize (Zea mays) that might cause corn lethal necrosis disease. MCMV transmission studies used six arthropod species found in MCMV-infected maize fields (Peregrinus maidis, Sardia pluto, Empoasca solana, Adoretus sinicus, Tetranychus sp. and Frankliniella williamsi). After a 1-3-day acquisition feeding period on MCMV-infected maize plants, five arthropod species gave positive test results for MCMV by enzyme-linked immunosorbent assay (EL-ISA), but only the thrips (F. williamsi) were able to transmit MCMV to healthy maize plants. This is the first evidence of MCMV transmission by thrips. MCMV was found in all maize genotypes tested and was detected by infectivity tests and ELISA in all parts of the maize plant and in mature seed with 13-30% moisture. Fifteen other species of plants tested by ELISA were negative for MCMV, except for one sample of the grass, Trichachne insularis, and one sample of the dicotyledon, Melia azedarach. However, only sap from maize plant parts testing positive for MCMV by ELISA was capable of infecting healthy maize plants. All maize samples from Kauai were negative (by ELISA) for maize chlorotic dwarf virus, wheat streak mosaic virus and maize dwarf mosaic virus strain A (MDMV-A); one maize sample out of 300 tested positive for MDMV strain B. One T. insularis sample tested positive for MDMV-A.