Particles of the rhabdovirus type in striate diseased pangola grass

A striate disease of pangola grass (Digiraria decumbans) has been recorded in Queensland since 1962. It is widely distributed and occurs from the South Coast districts to the Atherton Tableland in the north. The incidence, how' ever, is usually limited to 1 or 2 percent. Leaf symptoms may vary from fine chlorotic streaks parallel to the veins to broad chlorotic stripes covering most of the surface. In the field, infected plants are usually stunted but when transferred 10 a glasshouse often produce vigorous symptomless shoots. When sap preparations from diseased plants are negative· Iy stained with potassium phosphotungstate and examined in an electron microscope, bullet'shaped particles similar to those reported lor members of the Rhabdovirus group (1) are observed (figure ll. Groups of particles often appear to be associated with acommon membrane. Individual particles have a width of approximately 55 nm and occasionalJy show some evidence of surface projections beyond this dimension. The longest bullet·shaped particles have an average length of 280 nm and the central core is approxi· mately 18 nm. The periodicity of the cross·straitions measures 4.2 nm. No similar particles have been seen in sap from healthy pangola grass. Occurrence of the AI Mating Type of Phytophthora cinnamomi Rands on the South Coast of New South Wales