SPLASH DISPERSAL OF CONIDIA OF MYCOCENTROSPORA-ACERINA IN THE FIELD

The dispersal of conidia of Mycocentrospora acerina was studied in car away field trials. A Burkard spore trap, rotorods, inverted Petri dish es containing sucrose agar and rain gauges were used to trap conidia o f M. acerina. Sporulation was stimulated by rainfall (greater than or equal to 2 mm) and moderate temperatures (around 15 degrees C). Solar radiation had a negative effect on sporulation Hardly any conidia were found in the spore traps on rainless days. Short distance (less than or equal to 9 m) spread of M. acerina is mainly caused by splash dispe rsal of its conidia. Trap plants at 0, 0.1, 1 and 4 m from the inoculu m source were readily infected under moist conditions. Beyond 9 m from an inoculum source no infection of caraway trap plants was found. Tra p plants at 9 m from an inoculum source were infected in one out of th ree seasons only. Long distance (>9 m) spread could not be demonstrate d by the techniques used in this study. The results suggest that, usua lly, a caraway field is infected by inoculum sources within that field .