A Carrot Proliferation Disease Associated with Rickettsia-like Organisms in the Czech Republic

CarrOL plants showing severe proliferation sympt oms were obsen"cd in East Bohemia in 1996. Blue-white fluor..: sccnl arca~ were observed under nuorescence microscope in sieve tube cells of ~y Jl1p toll1atic planb. but nul in health) ones. Scanning eleclron microsco py revealed the presct1(:e of elo ngated struclUres in the phloem sic.::vc elements or diseased ca rrots. Transmission electron microscopy revealed rickettsia- like orga nisms prescnt in sicve tube e)cmcllls or "ymplomatic plants. The diametcr or thc bodies ranged rlʹolll about 0.2 0.3 tllll. Clnd the length of thlʹ elongated rorms reached 2.2Jlln. No other organisms werc detcch..:d. This is the !irst report of infcction by ~ ingle rickett sia-l ike orga nisms on carrot plant s.