EFFECT OF THE FUNGICIDE MANCOZEB ON FUNGI ASSOCIATED WITH SUGARCANE YIELD DECLINE IN QUEENSLAND

The broad spectrum fungicide mancozeb was applied to monocultured suga rcane soils affected by the growth constraint known as sugarcane yield decline. The constraint is associated with the long-term monoculture of sugarcane and has been shown to decrease sugarcane growth by 20% in commercial crops in Queensland. The fungicide was shown to decrease r oot colonization by soil fungi, particularly dematiaceous sterile fung i. Higher doses of mancozeb (up to 400 mg kg(-1)) sometimes led to inc reased populations of Penicillium spp. The fungicide greatly improved plant growth and root health when applied at doses of 100 mg kg(-1) an d above. Results suggest that She role of dematiaceous sterile fungi i n sugarcane yield decline should be further examined.