This research was completed for school science fairs, to see whether agricultural lime affects facial eczema spore numbers. Lime was applied at various rates on grazed plots, and using the Pithomyces chartarum (L) spore count wash method, the effect of lime on spore counts was measured. The residual effect of recent and past lime applications up to 3 years old was also measured. Lime applied at 2.5 tonnes/hectare killed nearly all of the spores within 5-8 days and maintained levels below the danger level of 50 000 spores/g for several weeks (whilst spores were present). As well as this short term effect, 2007 spore counts on plots last treated with lime in 2006 and 2005 averaged 44 167 and 35 833 spores/g respectively which were well below the 2007 control plot counts, which averaged 123 333 spores/g pasture. In these experiments, lime was effective at reducing facial eczema spore numbers when applied at 2.5 t/ha, with up to 2 year's residual effect. Therefore tactical use of lime applications could potentially protect farmers and stock from the effects of facial eczema for up to 3 years. Keywords: facial eczema, lime, Pithomyces chartarum (L), sporidesmin
